Ribbentrop was born in Wesel, Rhenish Prussia, the son of Richard Ulrich Friedrich Joachim Ribbentrop, a career army officer, and his wife Johanne Sophie Hertwig. Ribbentrop was educated irregularly at private schools in Germany and Switzerland. His father was cashiered from the Imperial German Army in 1908, following a series of disparaging remarks he had made about the alleged homosexuality of Kaiser Wilhelm II, and the Ribbentrop family were often short of money. Fluent in both French and English, young Ribbentrop lived at various times in Grenoble, France, and London, before traveling to Canada in 1910. He worked for the Molsons Bank on Stanley Street in Montreal and then for the engineering firm M.P. and J.T. Davis on the reconstruction of the Quebec Bridge. He was also employed by the National Transcontinental Railway, which constructed a line from Moncton to Winnipeg. He worked as a journalist in New York City and Boston and then rested to recover from tuberculosis in Germany. He returned to Canada and set up a small business in Ottawa importing German wine and champagne. In 1914, he competed for Ottawa's famous Minto ice-skating team, participating in the Ellis Memorial Trophy tournament in Boston in February.

When World War I began, Ribbentrop left Canada. He sailed from Hoboken, New Jersey, on 15 August 1914 on the Holland-America ship The Potsdam, bound for Rotterdam. He then returned home and enlisted in the 125th Hussar Regiment. He served first on the Eastern Front, but was later transferred to the Western Front. He earned a commission and was awarded the Iron Cross. In 1918 1st Lieutenant Ribbentrop was stationed in Istanbul as a staff officer. During his time in Turkey, he became friends with another staff officer named Franz von Papen.

In 1919 Ribbentrop met Anna Elisabeth Henkell, known as Annelies to her friends, daughter of a wealthy champagne producer from Wiesbaden. They married on 5 July 1920, and Ribbentrop travelled across Europe as a wine salesman. He and his wife would have five children: Rudolf von Ribbentrop (born 11 May 1921, in Wiesbaden), married in 1960 Ilse-Marie Freiin von Münchhausen (1914 – 2010); Bettina von Ribbentrop (born 20 July 1922, in Berlin); Ursula von Ribbentrop (born 29 December 1932, in Berlin); Adolf von Ribbentrop (born 2 September 1935, in Berlin), married first to Marion von Strempel and later to Maria de Mercedes Christiane Josefine Thekla Walpurga Barbara Gräfin und Edle Herrin von und zu Eltz genannt Faust von Stromberg (born 27 November 1951 at Eltville), and had two sons from each marriage; Barthold Henkell von Ribbentrop (born 19 December 1940, in Berlin), married to Brigitte von Trotha, the parents of Sebastian von Ribbentrop (born 3 February 1971), married on 12 May 2001 at Fuschl to Elisabethe/Isabelle Freiin Schuler von Senden (born 6 July 1975 in Munich). Annelies von Ribbentrop was often described as being a Lady Macbeth-type who dominated her husband. Ribbentrop persuaded his aunt Gertrud von Ribbentrop to adopt him on 15 May 1925, which allowed him to add the aristocratic von to his name. During the Weimar Republic era, Ribbentrop was apolitical and displayed no anti-Semitic prejudices. As a wealthy partner in the Henckel-Trocken champagne firm, Ribbentrop did business with Jewish bankers, and organized the Impegroma Importing Company ("Import und Export großer Marken") with Jewish financing.

In 1928, Ribbentrop was introduced to Hitler as a man who "gets the same price for German champagne as others get for French champagne" as well as a businessman with foreign connections. He joined the National Socialist German Workers' Party on 1 May 1932 at the urging of his wife, who herself joined the NSDAP at the same time. In January 1933, there was a complex set of intrigues which saw Franz von Papen and various friends of the President Paul von Hindenburg negotiating with Hitler to oust the Chancellor, General Kurt von Schleicher. The end result of these talks was the appointment of Hitler as Chancellor on 30 January 1933. Ribbentrop, who was both a Nazi Party member and an old friend of von Papen, facilitated the negotiations by arranging for von Papen and Hitler to meet secretly at his house in Berlin. This assistance endeared Ribbentrop to Hitler. Because Ribbentrop was a latecomer to the Nazi Party, the Alte Kämpfer (Old Fighters) of the party disliked him. The British historian Laurence Rees described Ribbentrop as "...the Nazi almost all the other leading Nazis hated" Typical of this hatred for Ribbentrop was the diary entry of Joseph Goebbels: "Von Ribbentrop bought his name, he married his money, and he swindled his way into office". To compensate for this, Ribbentrop became a fanatical Nazi, almost to the point of becoming a caricature of a Nazi brought to life. In particular, Ribbentrop became a vociferous anti-Semite.

He became German dictator Adolf Hitler's favourite foreign policy adviser, partly by dint of his knowledge of the world outside Germany, but mostly by means of shameless flattery and sycophancy. The professional diplomats of the elite Auswärtiges Amt (Foreign Office) told Hitler the truth about what was happening abroad in the early years of Nazi Germany; Ribbentrop told Hitler what he wanted Hitler to hear. One German diplomat, Herbert Richter, in an interview later recalled "Ribbentrop didn't understand anything about foreign policy. His sole wish was to please Hitler". In particular, Ribbentrop acquired the habit of listening carefully to what Hitler was saying, memorizing pet ideas of the Führer, and then later presenting Hitler's ideas as his own — a practice that much impressed Hitler as proving Ribbentrop was an ideal National Socialist diplomat. To assist with this, Ribbentrop always questioned those who had lunch with Hitler about what he had said, thereby allowing Ribbentrop at his next meeting with Hitler to present Hitler's ideas as his own. Ribbentrop quickly learned that Hitler always favored the most radical solution to any problem, and accordingly tended his advice in that direction. As one of Ribbentrop's aides, the SS man Reinhard Spitzy, recalled:

"When Hitler said 'Grey', Ribbentrop said 'Black, black, black'. He always said it three times more, and he was always more radical. I listened to what Hitler said one day when Ribbentrop wasn't present: 'With Ribbentrop it is so easy, he is always so radical. Meanwhile, all the other people I have, they come here, they have problems, they are afraid, they think we should take care and then I have to blow them up, to get strong. And Ribbentrop was blowing up the whole day and I had to do nothing. I had to break - much better!'"

Ribbentrop in turn was a great admirer of Hitler. Ribbentrop was emotionally dependent on Hitler's favor to the extent that he suffered from psychosomatic illnesses if Hitler was unhappy with him. In 1933 he was given the title of SS-Standartenführer. For a time, Ribbentrop was friendly with the Reichsführer-SS Heinrich Himmler, but ultimately the two became enemies mostly because the SS insisted upon the right to conduct its own foreign policy independent of Ribbentrop.

Ribbentrop began his work as an unofficial diplomat in the summer of 1933 with a series of visits to Paris. Using the intermediary of Fernand de Brinon, Ribbentrop was able to meet the French Premier Édouard Daladier in September 1933. Ribbentrop tried hard to set up a secret summit between Daladier and Hitler, only to be told by Daladier that the idea of a secret Franco-German summit was unacceptable as it was inevitable that the French press would discover the secret summit. When Ribbentrop persisted in trying to set up a secret Daladier-Hitler meeting, Daladier told him that "I live under a regime which does not allow me to move as freely as Herr Hitler" with Ribbentrop completely missing Daladier's sarcasm. In November 1933, Ribbentrop was able to arrange an interview between de Brinon, who was writing for the Le Matin newspaper and Hitler, during which Hitler stressed what he claimed to be his love of peace and his friendship towards France.

In November 1933, Ribbentrop made his first visit to London as an unofficial diplomat when he was able to use an old associate from his wine-selling days, the British whisky tycoon Ernest Tennant, to set up meetings with the Prime Minister Ramsay MacDonald, the Lord President Stanley Baldwin and Foreign Secretary Sir John Simon. Nothing of any substance emerged from these talks. Up to the time of his appointment as German Foreign Minister, Ribbentrop aggressively competed with the Auswärtiges Amt (Foreign Office) and sought to undercut the current Foreign Minister, Baron Konstantin von Neurath, at every turn. Initially, Neurath held his rival in contempt, regarding anyone whose written German, to say nothing of his English and French, was full of atrocious spelling and grammatical mistakes to be unworthy of attention. Speaking of views of Prince Bernard von Bülow, the State Secretary at the Auswärtiges Amt between 1930 – 1936 and the nephew of the former Chancellor Bernhard von Bülow, one contemporary recalled that "Bülow could not regard as a serious competitor a man who had no formal training in diplomacy, who could not write a report in correct German, who did not listen carefully enough to the remarks of foreign statesmen to interpret them correctly, and who insisted upon seeing possibilities of alliance [with Britain] where none existed".

In March 1934, Ribbentrop visited France, where he met the Foreign Minister Louis Barthou. During the meeting, Ribbentrop suggested that Barthou meet with Hitler at once to sign a Franco-German non-aggression pact. In response to German violations of Part V of the Treaty of Versailles, which had disarmed Germany, there had been several calls in France in 1933 for a preventive war before German rearmament was complete. Ribbentrop’s intention in proposing a 10 year Franco-German non-aggression pact was to buy time for completing German rearmament by removing preventive war as a French policy option. Barthou was forced to explain to Ribbentrop that he was not a dictator, and since France was a democracy, he would have to meet and discuss with the Cabinet before opening talks on a non-aggression pact. Barthou commented to Ribbentrop about Hitler that "The words are of peace, but the actions are of war". The Barthou-Ribbentrop meeting further estranged Neurath, who was infuriated that Ribbentrop met Barthou without bothering to inform the Auswärtiges Amt beforehand. In a report to President von Hindenburg, Neurath wrote:

"Such agents have often been active in the past and especially since the war. Their success and hence their usefulness is generally slight. In particular, it has been shown by experience that their connections are quickly used up. As soon as they meet with government members, the question concerning the official or semi-official nature of their instructions or mission is soon raised. Responsible statesmen naturally refuse to commit themselves to agents without responsibility. With that, the activity of these intermediaries in most cases comes to an end. Thus, in London recently Baldwin referred Herr Ribbentrop to Sir John Simon as the Minister responsible for questions of foreign policy. M. Barthou has now complained to Ambassador Köster about the manner of bringing in Herr Ribbentrop. From secret reports, it appears that M. Barthou was far from pleased with the visit and therefore treated Herr von Ribbentrop in a decidedly sarcastic manner...".

In April 1934, Ribbentrop was named Special Commissioner for Disarmament by Hitler, which made him part of the same Auswärtiges Amt that was the center of his competition with Neurath. After Ribbentrop's appointment as Special Commissioner, Neurath informed Erich Kordt, the diplomat assigned to Ribbentrop as his aide, not to correct any of Ribbentrop's spelling mistakes. Ribbentrop was given the office of Special Commissioner in large part because of doubts created in foreign capitals over just what precisely was his status as a diplomat. In his capacity as Special Commissioner, Ribbentrop frequently visited London, Paris and Rome. In his early years, Hitler's aim in foreign affairs was to persuade the world that he wished to reduce military spending by making idealistic but very vague offers of disarmament (in the 1930s, the term disarmament was used to describe arms-limitation agreements). At the same time, the Germans always resisted making concrete proposals for arms limitation, and they went ahead with increased military spending on the grounds that other powers would not take up German offers of arms limitation. Ribbentrop's task was to ensure that the world was convinced that Germany sincerely wanted an arms-limitation treaty while also ensuring that such a treaty never actually emerged. In the first part of his assignment, Ribbentrop was partly successful, but in the second part he more than fulfilled Hitler's expectations.

On 17 April 1934, French Foreign Minister Louis Barthou issued the so-called "Barthou note" terminating French involvement in the World Disarmament Conference on the grounds that Germany had been negotiating in bad faith, declaring henceforth that France would look after its own security. The aggressive tone of the "Barthou note" led to concerns on the part of Hitler that the next meeting of the Bureau of Disarmament of the League of Nations would see the French asking for sanctions against Germany for violating Part V of the Treaty of Versailles. Ribbentrop volunteered to stop the rumored sanctions, and visited London and Rome. During his visits, Ribbentrop met with Simon and Benito Mussolini, and asked them to postpone the next meeting of the Bureau of Disarmament, in exchange for which Ribbentrop offered nothing in return other than promises of better relations with Berlin. Despite Ribbentrop's efforts, the meeting went ahead as scheduled, but since no sanctions were sought against Germany, this led to Ribbentrop claiming success (in fact, Ribbentrop's efforts had nothing to do with the lack of sanctions). As Special Commissioner, Ribbentrop was allowed to see all diplomatic correspondence relating to the subject of disarmament, which Ribbentrop refused to share with Neurath or von Bülow. Due to Ribbentrop's perceived success in stopping sanctions being applied against Germany, Hitler ordered that Ribbentrop be allowed to see all diplomatic correspondence that was not "Marked for the Foreign Minister" or "For the Secretary of State". Ribbentrop used this privilege to go through the incoming diplomatic messages, snatching certain messages, taking them to Hitler and having a reply written without Neurath or Bülow being informed first.

In August 1934, Ribbentrop founded an organisation linked to the Nazi Party called the Büro Ribbentrop (later renamed the Dienststelle Ribbentrop) that functioned as an alternative foreign ministry. The Dienststelle Ribbentrop, which had its offices located directly across from the Auswärtiges Amt building on the Wilhelmstrasse in Berlin, had in its membership a collection of Hitlerjugend alumni, dissatisfied businessmen, former reporters, and ambitious Nazi Party members, all of whom tried to conduct a foreign policy independent of and often contrary to the Auswärtiges Amt. Though the Dienststelle Ribbentrop concerned itself with German foreign relations with every part of the world, a special emphasis was put on Anglo-German relations, as Ribbentrop knew an alliance with Britain was a project specially favored by Hitler. In the 1920s, Hitler had written that the principle goal of a future National Socialist foreign policy would be the "the destruction of Russia with the help of England”. As such, Ribbentrop worked hard during his early diplomatic career to realize Hitler’s dream of an anti-Soviet Anglo-German alliance. Ribbentrop made frequent trips to Britain, and upon his return he always reported to Hitler that the great mass of the British people longed for an alliance with Germany. In November 1934, Ribbentrop visited Britain where he met with George Bernard Shaw, Sir Austen Chamberlain, Lord Cecil, and Lord Lothian. On the basis of remarks from Lord Lothian praising the natural friendship between Germany and Britain, Ribbentrop informed Hitler that all elements of British society wished for closer ties with Germany, a report which delighted Hitler, causing him to remark that Ribbentrop was the only person who told him "the truth about the world abroad". Since the diplomats of the Auswärtiges Amt were not so sunny in their appraisal of the prospects of an Anglo-German alliance, Ribbentrop's influence with Hitler increased. Hitler later stated: "In 1933-34 the reports of the Foreign Office [Auswärtiges Amt] were miserable. They always had the same quintessence: that we ought to do nothing". By contrast, Hitler found that the reports of the extremely aggressive and energetic Ribbentrop were more in tune with what Hitler wanted to hear, leading to the influence of the former being much increased at the expense of the Auswärtiges Amt. Moreover, since Hitler regarded the diplomats of the Auswärtiges Amt as a collection of stodgy reactionaries out of touch with the spirit of "New Germany", the personality of Ribbentrop, with his disregard for diplomatic niceties, was in line with what Hitler felt should be the relentless dynamism of a revolutionary regime.

Ribbentrop was rewarded by Hitler by being made Reich Minister Ambassador-Plenipotentiary at Large (1935 – 1936). Ribbentrop then made numerous trips all over Europe, where he constantly presented various German proposals meant to upset the international order such as his 1935 offer to Belgium that Germany would renounce its claim to the Eupen-Malmedy region in exchange for a Belgian renunciation of the 1920 alliance with France. In 1935, Ribbentrop was able to arrange for a series of much publicized visits of World War I veterans to Britain, France and Germany. Ribbentrop persuaded the British Legion (the leading veterans' group in Britain) and many of the French veterans' groups to send delegations to Germany to meet German veterans as the best way of promoting peace. At the same time, Ribbentrop arranged for members of the Frontkämpferbund, the official German World War I veterans' group, to make visits to Britain and France to meet veterans there. The visits of the veterans with the attendant promises of "never again" with regards to war did much to improve the image of the "New Germany" in Britain and France. In July 1935, the visit of the British Legion delegation to Germany was headed by Brigadier Sir Francis Featherstone-Godley. Prince of Wales (who was the patron of the Legion), made a much publicized speech at the Legion's annual conference in June 1935 stating he could think of no better group of men than those of the Legion to visit and carry the message of peace to Germany, and stated that he hoped that Britain and Germany would never fight again.

Throughout his time as Ambassador at Large, Ribbentrop refused to share any information about his activities to the Auswärtiges Amt, who were very much frustrated by Ribbentrop's non-cooperative attitude. In his capacity as Ambassador-Plenipotentiary at Large, he negotiated the Anglo-German Naval Agreement (A.G.N.A.) in 1935 and the Anti-Comintern Pact in 1936. In regards to the former, Neurath did not think the A.G.N.A. was possible; to discredit his rival, he appointed Ribbentrop head of the delegation sent to London in June 1935 to negotiate it. Once the talks began, Ribbentrop, who possessed a certain elan and sense of audacity, issued Sir John Simon an ultimatum. He informed Simon that if Germany's terms were not accepted in their entirety, the German delegation would go home. Simon was angry with this demand and walked out of the talks under the grounds that "It is not usual to make such conditions at the beginning of negotiations". Much to everyone's surprise, the next day the British accepted Ribbentrop's demands and the A.G.N.A. was signed in London on 18 June 1935 by Ribbentrop and Sir Samuel Hoare, the new British Foreign Secretary. This diplomatic success did much to increase Ribbentrop's prestige with Hitler. Hitler called 18 June, the day the A.G.N.A. was signed, “the happiest day in my life” as he believed it marked the beginning of an Anglo-German alliance, and ordered celebrations throughout Germany to mark the event.

Immediately after the signing of the A.G.N.A., Ribbentrop followed up with the next step that was intended to create the Anglo-German alliance, namely the Gleichschaltung (co-ordination) of all societies demanding the restoration of the former German colonies in Africa into the Reichskolonialbund (Reich Colonial League) under General Franz Ritter von Epp. General von Epp in turn reported to Ribbentrop, who used the noisy agitation of the Reichskolonialbund to press for Germany's “inalienable” right to her former African colonies. It was the joint idea of Hitler and Ribbentrop that demanding colonial restoration would pressure the British into making an alliance with the Reich on German terms. However, there was a certain difference of opinion between Ribbentrop and Hitler in that Ribbentrop sincerely wished to recover the former German African colonies, whereas for Hitler, colonial demands were just a negotiating tactic that would see Germany “renounce” her colonial claims in exchange for a British alliance.

In the fall of 1935, Ribbentrop founded two "friendship societies" in Berlin, namely the Deutsch-Englische Gesellschaft for relations with Britain and the Deutsch-Französische Gesellscaft for relations with France. Both of the societies were closely linked to two other societies Ribbentrop had helped to create, the Comité France-Allemagne headed by Fernand de Brinon and the Anglo-German Fellowship headed at first by Ernest Tennant. Through his work with these societies, Ribbentrop worked to trying to convert elites in France and Britain into following a pro-German line.

In February 1936, when Hitler asked Neurath and Ribbentrop for their advice about whatever to remilitarize the Rhineland, Ribbentrop urged unilateral remilitarization at once. Ribbentrop went so far as to tell Hitler that if France attacked Germany because of the Rhineland, then Britain would come to Germany’s aid and attack France. Much to Neurath’s discomfort, Hitler found Ribbentrop’s advice more appealing than his own.

During a visit to London in April 1936, Ribbentrop met the Welsh political fixer and former civil servant Thomas Jones. As Sir Robert Vansittart, the Permanent Undersecretary at the British Foreign Office, was showing little interest in Ribbentrop's proposals for an Anglo-German alliance, Ribbentrop switched his efforts to cultivating Jones. As Jones was now in retirement (though he retained some influence through his friendship with the Prime Minister Stanley Baldwin), he was much impressed by Ribbentrop's efforts to cultivate him. Through Jones, Ribbentrop was able to meet Baldwin. Jones and Ribbentrop spent much of the spring and summer of 1936 attempting to set up a Hitler-Baldwin meeting only to be frustrated by Baldwin's dislike of travelling. At a meeting in May 1936, Jones told Baldwin that it was "a mistake to underestimate von Ribbentrop's influence and write him down as an ass because he does not adopt orthodox procedure. At the very least he is a reliable telephone from Hitler and the likelihood is that he is much more". Despite Jones's pleas, Baldwin was unmoved in refusing to make a trip to Germany.

The Anti-Comintern Pact of November 1936 marked an important change in German foreign policy. The Auswärtiges Amt had traditionally favoured a policy of friendship with China, one that Neurath very much believed in following. Ribbentrop was opposed to the pro-China orientation of the Auswärtiges Amt and instead favoured an alliance with Japan. To this end, Ribbentrop often worked closely with General Hiroshi Ōshima, who served first as the Japanese military attaché, and then as Ambassador in Berlin in strengthening German-Japanese ties, in spite of furious opposition from the Wehrmacht and the Auswärtiges Amt, who preferred closer Sino-German ties. The origins of the Anti-Comintern Pact went back to the summer and fall of 1935, when in an effort to square the circle between seeking a rapprochement with Japan and Germany’s traditional alliance with China, Ribbentrop, together with General Ōshima, devised the idea of an anti-Communist alliance as a way of binding China, Japan and Germany together. However, when the Chinese made it clear that they had no interest in such an alliance (especially given that the Japanese regarded Chinese adhesion to the proposed pact as a way of subordinating China to Japan), both Neurath and the War Minister Field Marshal Werner von Blomberg persuaded Hitler to shelve the proposed treaty in November 1935, lest it damage Germany's good relations with China. Ribbentrop for his part, who valued Japanese friendship far more than Chinese friendship, argued that Germany and Japan should sign the pact, even without Chinese participation. By November 1936, a revival of interest in a German-Japanese pact in both Tokyo and Berlin led to the signing of the Anti-Comintern Pact in Berlin. When the Pact was signed, invitations were sent out for Italy, China, Britain and Poland to adhere; of the invited powers, only the Italians were ultimately to sign the Anti-Comintern Pact. The Anti-Comintern Pact marked the beginning of the shift on Germany's part from China's ally to Japan's ally.

During the same period, Ribbentrop often visited France to try to influence, though not very successfully, French politicians into adopting a pro-German foreign policy. Ribbentrop enjoyed more success in the United Kingdom, where he was able to persuade an impressive array of British high society to visit Hitler in Germany. That Ribbentrop possessed the power to set up meetings with Hitler and represented himself as Hitler's personal envoy made him for a time a much courted figure in Britain. The most notable guest Ribbentrop brought to Hitler was the former Prime Minister David Lloyd George in 1936. Hitler's British guests were a mélange of aristocratic Germanophiles such as Lord Londonderry, professional pacifists such as George Lansbury and Lord Allen, retired politicians, ex-generals, fascists such as Admiral Barry Domvile and Sir Oswald Mosley, journalists such as Lord Lothian and G. Ward Price, academics such as the historian Philip Conwell-Evans, and various businessmen like the newspaper magnate Lord Rothermere and the merchant banker Lord Mount Temple. Very few of these people were actual decision-makers in the British government, such as Cabinet-level politicians or high-ranking bureaucrats. Neither Hitler nor Ribbentrop understood very well that when people like Lloyd George, Londonderry, Lansbury, Mount Temple, Allen, Lothian or Rothermere declared that they favoured closer Anglo-German ties, they were speaking as private citizens, not on behalf of Whitehall. As a German diplomat, Truetzschler von Falkenstein complained after the war that "Ribbentrop, having had contact with only a small group in England – representatives of the so-called two hundred families – did not know the great mass of the English people. The England with which he had hoped to collaborate was the England of this select group, since he believed that its members controlled Britain". Another German diplomat commented that Ribbentrop had the strange idea to "conduct international relations through aristocrats". Yet another German diplomat noted that, "He [Ribbentrop] did not have the capacity to form an overview; to see things in perspective. In England, for example, he relied upon people like Conwell-Evans who had no real influence". Earlier, speaking of Ribbentrop's activities and of the views of his British friends, Leopold von Hoesch, the German Ambassador in London from 1932–36, warned that Berlin should "...not pay any attention to the Londonderrys and Lothians, who in no way represented any important section of British opinion".

In August 1936, the German government appointed Ribbentrop Ambassador to Britain with orders to negotiate the Anglo-German alliance that Hitler had predicted in Mein Kampf. Ribbentrop arrived to take up his position in October 1936. The two month delay between Ribbentrop's appointment and his arrival in London was due to the fracas caused by the death of the Auswärtiges Amt's State Secretary Prince von Bülow in July 1936. Ribbentrop immediately suggested to Hitler that he succeed Bülow as State Secretary. Neurath informed Hitler that he would rather resign than have Ribbentrop as State Secretary and proceeded to appoint his son-in-law Hans Georg von Mackensen to that office. Hitler, for his part, had been highly impressed by Neurath's skillful efforts at defusing the crisis caused by remilitarization of the Rhineland in March 1936, and moreover felt that Ribbentrop's talents better suited him to serving as Ambassador than as State Secretary. Ribbentrop, who would have much preferred to be State Secretary than Ambassador, spent the next two months attempting to persuade Hitler to give him the former office rather than the latter before reluctantly leaving for Britain in October 1936. Before leaving to take up his post in London, Ribbentrop was commissioned by Hitler:

“Ribbentrop...get Britain to join the Anti-Comintern Pact, that is what I want most of all. I have sent you as the best man I’ve got. Do what you can... But if in future all our efforts are still in vain, fair enough, then I’m ready for war as well. I would regret it very much, but if it has to be, there it is. But I think it would be a short war and the moment it is over, I will then be ready at any time to offer the British an honorable peace acceptable to both sides. However, I would then demand that Britain join the Anti-Comintern Pact or perhaps some other pact. But get on with it, Ribbentrop, you have the trumps in your hand, play them well. I'm ready at any time for an air pact as well. Do your best. I will follow your efforts with interest”.

The vain, arrogant, and tactless Ribbentrop was not the man for such a mission, but it is doubtful that even a more skilled diplomat could have fulfilled Hitler's dream of a grand Anglo-German alliance. His time in London was marked by an endless series of social gaffes and blunders that worsened his already poor relations with the British Foreign Office (Punch referred to him as Von Brickendrop and the Wandering Aryan due to his frequent trips back to Germany.) Upon arriving in Britain on October 26, 1936, Ribbentrop created a storm in the British press by reading the following statement:

"Germany wants to be friends with Great Britain and, I think, the British people also wish for German friendship. The Führer is convinced that there is only one real danger to Europe and to the British Empire as well, and that is the spreading further of communism, this most terrible of all diseases - terrible because people generally seem to realize its danger only when it is too late. A closer collaboration in this sense between our two countries is not only important but a vital necessity in the common struggle for the upholding of our civilization and our culture".

The Daily Telegraph newspaper commented that it was regrettable that the new German ambassador could offer no better basis for improved Anglo-German relations beyond a common hatred for a third country. To help with his move to London, and with the design of the new German Embassy Ribbentrop had built (the existing Embassy was deemed insufficiently grand for Ribbentrop), Ribbentrop hired a Berlin interior decorator named Martin Luther. Upon the recommendation of his wife, Ribbentrop hired Luther to work for the Dienststelle Ribbentrop. Luther proved to be a master intriguer, and became Ribbentrop's favorite hatchet man.

Besides working to achieve Hitler's dream of an Anglo-German alliance against the Soviet Union, Ribbentrop served as the German delegate for the Non-Intervention Committee for the Spanish Civil War in London. Since Germany was in fact intervening in the civil war in Spain, Ribbentrop's purpose at the Non-Intervention Committee was to frustrate and sabotage the workings of the committee as much as possible.

Ribbentrop did not understand the King's limited role in government as he thought King Edward VIII could decide British foreign policy. He convinced Hitler that he had Edward's support; but this, like his belief that he had impressed British society, was a tragic delusion. Ribbentrop often woefully misunderstood both British politics and society. During the abdication crisis of December 1936, Ribbentrop reported to Berlin that the reason the crisis had occurred was an anti-German Jewish-Masonic-reactionary conspiracy to depose Edward (whom Ribbentrop represented as a staunch friend of Germany), and that civil war would soon break out in Britain between supporters of the King and supporters of the Prime Minister, Stanley Baldwin. Ribbentrop's statements about the abdication crisis causing a civil war were greeted with much incredulity by those British people who heard them. This led to a false sense of confidence about British intentions with which he unwittingly deceived his Führer.

Ribbentrop's time as Ambassador was notable as he threw the German Embassy into a total state of chaos due to his erratic personality. Ribbentrop's aide, the SS man Reinhard Spitzy, described a typical day working for Ribbentrop as:

"He [Ribbentrop] rose, muttering bad-temperedly...Dressed in his pyjamas, he received the junior secretaries and press attachés in his bathroom...He scolded, threatened, gesticulated with his razor and shouted at his valet...As he took his bath, he ordered people to be summoned from Berlin, accepted and cancelled, appointed and dismissed, and dictated through the door to a nervous stenographer...He cursed people in their absence, calling them saboteurs and communists... It was my task to put his calls through; his valet stood within splashing distance holding a white telephone... Ribbentrop believed only ministers ranked above him: everyone else, including his ambassadorial colleagues, had to be kept waiting on the line. Sometimes they did not share this view and rang off. The outburst of rage which ensured was directed against me..

'Mr. X', I would eventually say,'has been asked to call at ten o'clock and it is already nine-thirty. Shall I cancel or postpone the appointment?'.

'Better cancel or postpone. No, get him to wait until he's blue in the face, but you had better cancel all the other appointments. I must write to the Führer today!' (In fact, during the whole period I worked for him, Ribbentrop only managed to complete about five such letters. But how often he planned them! He prepared endless drafts which he spread out on the floor. In the evening they usually ended up in the fireplace)...I longed for the moment when it was the turn of the protocol officials to come in and I could make my escape...Then I had to deal with the brigade of tailors, bootmakers, shirtmakers and other craftsmen who had been summoned from the best London firms, and had to be consoled with appointments for the following day. They withdrew, to report at the houses of other clients on the ill manners of the ambassadorial couple....

At about eleven-thirty he would finally appear at his office. His waiting room would be crammed with impatient messengers, visitors, diplomats, officials... I had to console them with feeble excuses such as that His Excellency was not very well, or engaged in an urgent state call to Berlin...For the rest of the morning he listened to reports from members of the Embassy staff, unless I had to accompany him to the [British] Foreign Office...When Ribbentrop strutted through the [Foreign Office] corridors like a peacock, his head thrown back, it was a miracle that he did not fall over. His deportment aroused great mirth among the British officials, who often grinned at me with a pitying look...."

Ribbentrop's habit of summoning tailors from the best British firms, making them wait for hours and then sending them away without seeing him with instructions to return the next day, only to repeat the process, did immense damage to his reputation in British high society. As a result of Ribbentrop's abusive behavior towards the tailors of London, the tailors retaliated by telling all of their other well-off clients what an impossible man Ribbentrop was to deal with. In an interview, Spitzy stated "He [Ribbentrop] behaved very stupidly and very pompously and the British don't like pompous people". In the same interview, Spitzy called Ribbentrop "pompous, conceited and not too intelligent", and stated he was an utterly insufferable man to work for. In addition, the fact that Ribbentrop chose to spend as little time as possible in London in order to stay close to Hitler irritated the British Foreign Office immensely, as Ribbentrop's frequent absences prevented the handling of many routine diplomatic matters. As Ribbentrop progressively starting alienating more and more people in Britain, Hermann Göring warned Hitler that Ribbentrop was a "stupid ass". Hitler dismissed Göring's concerns by saying "But after all, he knows quite a lot of important people in England", leading Göring to reply "Mein Führer, that may be right, but the bad thing is, they know him".

In February 1937, Ribbentrop committed a notable social gaffe by unexpectably greeting King George VI with a "Heil Hitler!" Nazi salute which nearly knocked the King over as he walked forward to shake Ribbentrop's hand. Ribbentrop further compounded the damage to his image and caused a minor crisis in Anglo-German relations by insisting that hencefoward all German diplomats were to greet heads of state with the "German greeting", who were in turn to return the fascist salute. The crisis was resolved when Neurath pointed out to Hitler that under Ribbentrop's rules, if the Soviet Ambassador were to give the Communist clenched fist salute, then Hitler would be obliged to return it. As a result of Neurath's advice, Hitler disavowed Ribbentrop over his demands that King George receive and give the "German greeting".

In his dealings with the British government, most of Ribbentrop's time was spent either demanding that Britain sign the Anti-Comintern Pact or that London return the former German colonies in Africa. Other than his fruitless meetings with the British Foreign Secretary Sir Anthony Eden, who always refused on behalf of his government Ribbentrop's demands about the former colonies or the Anti-Comintern Pact, Ribbentrop spent most of his time as Ambassador courting what Ribbentrop called the “men of influence” as the best way of bringing about an Anglo-German alliance. Ribbentrop had developed the notion that the British aristocracy comprised some sort of secret society that ruled from behind the scenes, and if he could befriend enough members of Britain's “secret government”, then he could bring about an alliance with his country. Almost all of the initially favorable reports Ribbentrop provided to Berlin about the prospects of an Anglo-German alliance were based on friendly remarks about the “New Germany” from various British aristocrats like Lord Londonderry and Lord Lothian; the rather cool reception that Ribbentrop received from British Cabinet ministers and senior bureaucrats did not make much of an impression on him at first. In 1935, Sir Eric Phipps, the British Ambassador to Germany, complained to London about Ribbentrop's British associates in the Anglo-German Fellowship, that they created "false German hopes as in regards to British friendship and caused a reaction against it in England, where public opinion is very naturally hostile to the Nazi regime and its methods". In September 1937, the British Consul in Munich, writing about the group Ribbentrop had brought to the Nuremberg Party Rally, reported that there were some "serious persons of standing among them" and that an equal number of Ribbentrop's British contingent were "eccentrics and few, if any, could be called representatives of serious English thought, either political or social, while they most certainly lacked any political or social influence in England". In June 1937, when Lord Mount Temple, the Chairman of the Anglo-German Fellowship, asked to see the British Prime Minister Neville Chamberlain after meeting Hitler in a visit arranged by Ribbentrop, Robert Vansittart, the British Foreign Office's Undersecretary wrote a memo stating that:

"The P.M. [Prime Minister] should certainly not see Lord Mount Temple – nor should the S[ecretary] of S[tate]. We really must put a stop to this eternal butting in of amateurs – and Lord Mount Temple is a particularly silly one. These activities – which are practically confided to Germany – render impossible the task of diplomacy. Lord Londonderry goes to Berlin; Lord Lothian goes to Berlin; Mr. Lansbury goes to Berlin; and now Lord Mount Temple goes. They all want interviews with the S of S, and two at least have had them. This flow is quite unfair to the service and Sir E. Phipps rightly complained of these ambulant amateurs. So did Sir N. Henderson in advance, and rightly, for Lord Lothian's last visit is being mischievously and unintelligently misused, particularly at the Imperial Conference. The proper course for any ambulant amateur is to be seen by someone less important than Ministers. If there is anything worthwhile in their remarks – there never is, for, of course, we have much better information than this naïf propaganda stuff – we can report it to the S of S. But a stage has now been reached where the service is entitled to at least this amount of protection. These superficial people are always gulled into the lines of least resistance – vide Lord Lothian – and we then have the ungrateful but necessary task of pointing out the snags and appearing obstructive. It is quite unfair and should cease”.

After Vansittart's memo, members of the Anglo-German Fellowship ceased to see Cabinet ministers after going on Ribbentrop-arranged trips to Germany. One of the "men of influence" Ribbentrop attempted to win over was Winston Churchill (who in fact in 1937 possessed little influence), who during a 1937 meeting told him that though most people in Britain hated communism, neither the British government or British people wanted an anti-Soviet alliance with Germany nor would they accept a pro quid quo in which Britain would abandon Europe to Germany in exchange for German support for maintaining the British Empire. Ribbentrop then told Churchill if Britain would not ally herself with Germany, then the Germans would have no other choice, but to destroy the British Empire, leading Churchill to reply that the last time the Germans tried that, it was the German Empire that ended up being destroyed.

In February 1937, prior to a meeting with the Lord Privy Seal, Lord Halifax, Ribbentrop suggested to Hitler that Germany together with Italy and Japan began a worldwide propaganda campaign with the aim of forcing Britain to return the former German colonies in Africa. Hitler turned down this idea of Ribbentrop’s, but nonetheless during his meeting with Lord Halifax, Ribbentrop spent much of the meeting demanding that Britain sign an alliance with Germany and return the former German colonies. The German historian Klaus Hildebrand noted that as early as the Ribbentrop–Halifax meeting the differing foreign policy views of Hitler and Ribbentrop were starting to emerge with Ribbentrop more interested in restoring the pre-1914 German Imperium in Africa than conquest of Eastern Europe. Following the lead of Andreas Hillgruber, who argued that Hitler had a stufenplan (stage by stage plan) for world conquest, Hildebrand argued that Ribbentrop may not have fully understood what Hitler’s stufenplan was, or alternatively in pressing so hard for colonial restoration was trying to score a personal success that might improve his standing with Hitler. In March 1937, Ribbentrop attracted much adverse comment in the British press when he gave a speech at the Leipzig Trade Fair in Leipzig, where he declared that German economic prosperity would be satisfied either "through the restoration of the former German colonial possessions, or by means of the German people's own strength”. The implied threat that if colonial restoration did not occur, then the Germans would take back by force their former colonies attracted a large deal of hostile commentary on the inappropriateness of an Ambassador threatening his host country in such a manner.

His aggressive and overbearing manner towards everyone except his wife and Hitler meant that to know him was to dislike him. His negotiating style, a strange mix of bullying bluster and icy coldness coupled with lengthy monologues praising Hitler, alienated many. The American historian Gordon A. Craig once observed that of all the voluminous memoir literature of the diplomatic scene of 1930s Europe, there are only two positive references to Ribbentrop. Of the two references, General Leo Geyr von Schweppenburg, the German military attaché in London, commented that Ribbentrop had been a brave soldier in World War I, while the wife of the Italian Ambassador to Germany, Elisabetta Cerruti, called Ribbentrop "one of the most diverting of the Nazis". In both cases the praise was limited, with Cerruti going on to write that only in the Third Reich was it possible for someone as superficial as Ribbentrop to rise to be a minister of foreign affairs, while Geyr von Schweppenburg called Ribbentrop an absolute disaster as Ambassador in London. The British historian/television producer Laurence Rees noted for his 1997 series The Nazis A Warning from History that every single person interviewed for the series who knew Ribbentrop expressed a passionate hatred for him. One German diplomat, Herbert Richter, called Ribbentrop "lazy and worthless" while another, Manfred von Schröder, was quoted as saying Ribbentrop was "vain and ambitious". Rees concluded that "No other Nazi was so hated by his colleagues".

In November 1937, Ribbentrop was placed in a highly embarrassing situation when his forceful advocacy of the return of the former German colonies led to the British Foreign Secretary Anthony Eden and the French Foreign Minister Yvon Delbos offering to open talks on returning the former German colonies, in return for which the Germans would make binding commitments to respect their borders in Central and Eastern Europe. Since Hitler was not really interested in obtaining the former colonies, especially if the price was a brake on expansion into Eastern Europe, Ribbentrop was forced to turn down the Anglo-French offer that he had largely brought about. Immediately after turning down the Anglo-French offer on colonial restoration, Ribbentrop for reasons of pure malice ordered the Reichskolonialbund to increase the agitation for the former German colonies, a move which exasperated both the Foreign Office and Quai d'Orsay.

Ribbentrop's inability to achieve the alliance that he had been sent out for frustrated him, as he feared it could cost him Hitler's favour, and it made him a bitter Anglophobe. As the Italian Foreign Minister, Count Galeazzo Ciano, noted in his diary in late 1937, Ribbentrop had come to hate Britain with all the “fury of a woman scorned”. Ribbentrop, and Hitler for that matter, never understood that British foreign policy aimed at the appeasement of Germany, not an alliance.

When Ribbentrop travelled to Rome in November 1937 to oversee Italy's adhesion to the Anti-Comintern Pact, he made clear to his hosts that the pact was really directed against Britain. As Count Ciano noted in his diary, the Anti-Comintern Pact was "anti-Communist in theory, but in fact unmistakably anti-British". Believing himself to be in a state of disgrace with Hitler over his failure to achieve the British alliance, Ribbentrop spent December 1937 in a state of depression, and together with his wife, wrote two lengthy documents for Hitler denouncing Britain. In the first of his two reports to Hitler, which was presented on 2 January 1938, Ribbentrop stated that "England is our most dangerous enemy". In the same report, Ribbentrop advised Hitler to abandon the idea of a British alliance, and instead embrace the idea of an alliance of Germany, Japan and Italy, who would destroy the British Empire. Ribbentrop wrote:

"I have worked for many years for friendship with England and nothing would make me happier than if it could be achieved. When I asked the Führer to send me to London, I was sceptical whether it would work. However, in view of Edward VIII, a final attempt seemed appropriate. Today I no longer believe in an understanding. England does not want a powerful Germany nearby which would pose a permanent threat to the islands".

Ribbentrop wrote in his "Memorandum for the Führer" that "a change in the status quo in the East to Germany's advantage can only be accomplished by force", and that the best way to achieve this change was to build a global anti-British alliance system. Besides converting the Anti-Comintern Pact into an anti-British military alliance, Ribbentrop argued that German foreign policy should work to "furthermore, winning over all states whose interests conform directly or indirectly to ours". By the last statement, Ribbentrop clearly implied that the Soviet Union should be included in the anti-British alliance system he had proposed. Ribbentrop ended his memo with the advice to Hitler that: "Henceforth - regardless of what tactical interludes of conciliation may be attempted with regard to us - every day that our political calculations are not actuated by the fundamental idea that England is our most dangerous enemy would be a gain to our enemies".

While the Ribbentrops were in Britain, his son, Rudolf von Ribbentrop, attended Westminster School in London. Peter Ustinov was Rudolf's schoolmate at this time, as related in his autobiography Dear Me (1971). Ustinov is also supposed to have clandestinely leaked Rudolf's presence at his school to The Times. The result of this was the prompt withdrawal of the younger Ribbentrop from the school as a precautionary measure for his safety, as well as for security of his father's mission in London.

Ribbentrop's time in London was also marked by scandal. It was believed by many members of the British upper classes that he was having an affair with Wallis Simpson, the wife of British businessman Edward Simpson and the mistress of King Edward VIII. According to files recently declassified by the United States Federal Bureau of Investigation, Mrs. Simpson was believed to be a regular guest at Ribbentrop's social gatherings at the German Embassy in London where it was thought the two struck up a romantic relationship. It was believed by the Americans at the time that Ribbentrop was said to have used Simpson's access to the King to funnel important information about the British to the German government. Supposedly, Simpson was paid by the Germans for this information and was happy to continue the relationship as long as she received payment. The FBI took the matter seriously enough to advise President Roosevelt of their findings; he once commented to a confidante that Simpson "played around... with the Ribbentrop set." The truth of the matter is still very much in doubt. Simpson, who later married the former king – he had abdicated to marry her – and was known in later life as the Duchess of Windsor, noted in her book The Heart Has Its Reasons that she met Ribbentrop on only two occasions and had no personal relationship with him.

On 5 November 1937, the conference between the Reich’s top military-foreign policy leadership and Hitler recorded in the so-called Hossbach Memorandum occurred. At the conference, Hitler stated that it was the time for war, or, more accurately, wars, as what Hitler envisioned were a series of localized wars in Central and Eastern Europe in the near future. Hitler argued that because these wars were necessary to provide Germany with Lebensraum, autarky and the arms race with France and Britain made it imperative to act before the Western powers developed an insurmountable lead in the arms race. Of those invited to the conference, objections arose from Neurath, the War Minister Field Marshal Werner von Blomberg, and the Army Commander in Chief, General Werner von Fritsch that any German aggression in Eastern Europe was bound to trigger a war with France because of the French alliance system in Eastern Europe, the so-called cordon sanitaire, and if a Franco-German war broke out, then Britain was almost certain to intervene rather than risk the prospect of France’s defeat. Moreover, it was objected that Hitler's assumption that Britain and France would just ignore the projected wars because they had started their re-armament later than Germany was flawed. Accordingly, Fritsch, Blomberg and Neurath advised Hitler to wait until Germany had more time to re-arm before pursuing a high-risk strategy of localized wars that was likely to trigger a general war before Germany was ready (none of those present at the conference had any moral objections to Hitler’s strategy, with which they were in basic agreement; only the question of timing divided them). Hitler was most displeased with the criticism of his intentions, and in early 1938 asserted his control of the military-foreign policy apparatus through the Blomberg-Fritsch Affair, the abolition of the War Ministry and its replacement by the OKW, and finally by sacking Neurath as Foreign Minister on 4 February 1938. In the opinion of the official German history of World War II, from early 1938 Hitler was not carrying out a foreign policy that had carried a high risk of war, but was carrying out a foreign policy aiming at war. Ribbentrop was chosen as Neurath’s successor as Hitler judged the former would be a more willing instrument to realize Hitler’s foreign policy than the latter.

On 4 February 1938, Ribbentrop succeeded Baron Konstantin von Neurath as Foreign Minister. Ribbentrop's appointment was generally taken at the time and since as indicating that German foreign policy was moving in a more radical direction. In contrast to Neurath's less bellicose and cautious nature, Ribbentrop unequivocally supported war in 1938-39. In May 1938 Benito Mussolini commented after meeting Ribbentrop that:

"Ribbentrop belongs to the category of Germans who are a disaster for their country. He talks about making war right and left, without naming an enemy or defining an objective".

Under Ribbentrop's influence, Hitler grew increasingly anti-British, through he never fully embraced Ribbentrop's anti-British foreign policy programme, which as the German historian Andreas Hillgruber noted was the "very opposite" of Hitler's foreign programme which saw an anti-Soviet alliance with Britain as the best course. Ribbentrop's time as Foreign Minister can be divided into three periods. In the first, from 1938 – 39, he tried to persuade other states to align themselves with Germany for the coming war. In the second from 1939 – 43, Ribbentrop attempted to persuade other states to enter the war on Germany's side or at least maintain pro-German neutrality. In the final phase from 1943 – 45, he had the task of trying to keep Germany's allies from leaving her side. During the course of all three periods, Ribbentrop met frequently with leaders and diplomats from Italy, Japan, Romania, Spain, Bulgaria, and Hungary. During all this time, Ribbentrop feuded with various other Nazi leaders; at one point in August 1939 an armed clash took place between supporters of Ribbentrop and those of Propaganda Minister Joseph Goebbels over the control of a radio station in Berlin that was meant to broadcast German propaganda abroad (Goebbels claimed exclusive control of all propaganda both at home and abroad whereas Ribbentrop asserted a claim to monopolize all German propaganda abroad). As Foreign Minister, Ribbentrop was highly concerned with counteracting the damage that he himself inflicted on the influence of the Auswärtiges Amt. Friedrich Gaus, the chief of the Legal Division of the Auswärtiges Amt testified at the Nuremberg war crimes trials that:

"He [Ribbentrop] used to say, that everything the Foreign Office lost in the way of terrain under Neurath he wanted to win back and, with all his passion, he fought for this aim in a manner which can only be understood by somebody who actually saw it".

Gaus went on to testify that "My main activity was 90 per cent concerned with competency conflicts". Moreover, as time went by, Ribbentrop started to oust the old diplomats from their senior positions in the Auswärtiges Amt and replaced them with men from the Dienststelle. As early as 1938, 32% of the offices in the Foreign Ministry were held by men who previously served in the Dienststelle. Ribbentrop was widely disliked by the old diplomats in Auswärtiges Amt. Herbert von Dirksen who served as Ribbentrop's successor as German Ambassador in London in 1938 - 1939 described Ribbentrop as "an unwholesome, half-comical figure". Dirksen was to later write that he at first hoped that now that Ribbentrop was Foreign Minister this would mean the end of the Dienststelle "for no man can intrigue against himself. That Ribbentrop was able to perform even this miracle only came home to me much later". Many of the people Ribbentrop appointed to head German embassies, especially the "amateur" diplomats from the Dienststelle were grossly incompetent, thus limiting the effectiveness of the Auswärtiges Amt.

One of Ribbentrop's first acts as Foreign Minister was to achieve a total volte-face in Germany's Far Eastern policies. Ribbentrop was instrumental in February 1938 persuading Hitler to recognize the Japanese puppet state of Manchukuo and to renounce German claims upon her former colonies in the Pacific, which were now held by Japan. By April 1938, Ribbentrop had ended all German arms shipments to China and had all of the German Army officers serving with the Kuomintang government of Chiang Kai-shek recalled (with the threat that the families of the officers in China would be sent to concentration camps if the officers did not return to Germany immediately). In return, the Germans received little thanks from the Japanese, who refused to allow any new German businesses to be set up in the part of China they had occupied, and continued with their policy of attempting to exclude all existing German (together with all other Western) businesses from Japanese-occupied China. At the same time, the ending of the informal Sino-German alliance led Chiang to terminate all of the concessions and contracts held by German companies in Kuomintang China.

As Foreign Minister, Ribbentrop was noted for his virulent Anglophobia and anti-Semitism. Although he was almost lackey-like in Hitler's presence, he could be boorish when he was alone. At a meeting between Ribbentrop, Hitler and Henderson on 3 March 1938 during which Henderson offered on behalf of his government a proposal for an international consortium to rule much of Africa, in which Germany would play a leading role in exchange for which Germany would agree not to change its borders through violence, the British offer was flatly refused by Hitler, who had no real interest in colonies in Africa, and was more interested in the idea of Lebensraum or expansionism, in Eastern Europe. At the same meeting, Ribbentrop stated that the British government secretly controlled the British press, and hence could silence at any moment all press criticism of the Nazi regime; the fact that the British government had not done so was proof of British malevolence towards Germany. After the meeting, Henderson reported to the British Foreign Secretary Lord Halifax about a private conversation he had with Ribbentrop: "He [Ribbentrop] talked so much... about what Great Britain should do that I warned at last that you [Lord Halifax] would be expecting rather to hear what Germany would be prepared to do. His reply was: "What can we do? We have nothing to give". Ribbentrop loathed Neville Chamberlain, and viewed his appeasement policy as some sort of British scheme to block Germany from her rightful place in the world. Chamberlain for his part after meeting Ribbentrop in February 1938 wrote in a letter to his sister that he found Ribbentrop to be "so stupid, so shallow, so self-centered and so self-satisfied, so totally devoid of intellectual capacity, that he never seems to take in what is said to him".

During the May Crisis of 1938, Ribbentrop boastfully told the British Ambassador, Sir Nevile Henderson that Germany was prepared to struggle to the death with Britain and France, and that in regards to Czechoslovakia "...there would not be a living soul in that state". In response to objections from Baron Ernst von Weizsäcker, (the Auswärtiges Amt State Secretary 1938 - 1943) in August 1938 that if Germany attacked Czechoslovakia, it would cause a world war that Germany could not win, Ribbentrop replied: "...the Führer had never yet been wrong...One must believe in his genius as he, Ribbentrop, did, from long years of experience. If I had not yet come to blind faith in this matter, he urged me to do so". Before the Anglo-German summit at Berchtesgaden on September 15, 1938, Henderson and Weizsäcker worked out a private arrangement that Hitler and Chamberlain were to meet with no advisers present as a way of excluding the ultra-hawkish Ribbentrop from attending the talks. Hitler's interpreter Paul Schmidt later recalled that it was "felt that our Foreign Minister would prove a disturbing element" at the Berchtesgaden summit. In a moment of pique at his exclusion from the Chamberlain - Hitler meeting, Ribbentrop refused to hand over to Chamberlain Schmidt's notes of the summit, a move which caused much annoyence on the British side. Ribbentrop spent the last weeks of September 1938 very much looking forward to the German - Czechoslovak war he expected to break out on October 1, 1938. Ribbentrop regarded the Munich Agreement as a diplomatic defeat for Germany, as it deprived Germany of the opportunity to wage the war to destroy Czechoslovakia that Ribbentrop wanted to see; the Sudetenland issue, which was the ostensible subject of the German - Czechoslovak dispute, had been just a pretext for German aggression. During the Munich Conference, Ribbentrop spent much of his time brooding unhappily in the corners. Ribbentrop told the head of Hitler's Press Office, Fritz Hesse that the Munich Agreement was "first-class stupidity... All it means is that we have to fight the English in a year, when they will be better armed... It would have been much better if war had come now". Like Hitler, Ribbentrop was determined that in the next crisis, Germany would not have its professed demands met in another Munich-type summit, and that the next crisis to be caused by Germany would result in the war that Chamberlain had “cheated” the Germans out of at Munich.

In the aftermath of Munich, Hitler was in a violently anti-British mood caused in part over his rage over being “cheated” out of the war to “annihilate” Czechoslovakia that he very much wanted to have in 1938, and in part by his realization that Britain would neither ally herself nor stand aside in regards to Germany’s ambitions to dominate Europe. As a consequence, after Munich, Britain was considered to be the main enemy of the Reich, and as a result, the influence of ardently Anglophobic Ribbentrop correspondingly rose with Hitler. Starting in the fall of 1938, Ribbentrop attempted to convert the Anti-Comintern Pact into an anti-British military alliance, without much success. Much to Ribbentrop's intense disappointment, the Japanese were more interested in 1938-39 in fighting the Soviets and the Chinese rather than fighting the British. The Japanese were willing to see the Anti-Comintern Pact converted into a military alliance, but only against the Soviet Union. Unknown to Ribbentrop, the differences in opinion during the winter of 1938-39 between Japan and Germany about whether to convert the Anti-Comintern Pact into an anti-British or an anti-Soviet military alliance were known to the Kremlin thanks to the fact that the Soviets had broken the Japanese diplomatic codes and through the spy ring in Tokyo headed by Richard Sorge.

As part of the anti-British course, it was deemed necessary in Germany to have Poland as either a satellite state or otherwise neutralized. The Germans believed this necessary on both strategic grounds as a way of securing the Reich’s eastern flank and on economic grounds as a way of evading the effects of a British blockade. Starting in October 1938, Ribbentrop during several meetings with the Polish Ambassador to Germany Józef Lipski and the Polish Foreign Minister Colonel Józef Beck expressed his wishes that Poland agree to the return of the Free City of Danzig (modern Gdańsk, Poland) to the Reich, allow for “extra-territorial” highways across the Polish Corridor to East Prussia, and most importantly, sign the Anti-Comintern Pact (the last gesture was generally understood as placing Poland within the German sphere of influence). At a meeting with Lipski in October 1938, Ribbentrop stated that he wanted eine Gesamtlösung (total settlement) between Germany and Poland with Poland being reduced to a subordinate state to the Reich within the Anti-Comintern Pact.

In October-November 1938, Ribbentrop together with the Italian Foreign Minister Count Galeazzo Ciano, delegations led by the Czecho-Slovak foreign minister František Chvalkovský, and the Hungarian foreign minister Count Kálmán Kánya conducted negotiations in Vienna that resulted in the First Vienna Award over the fate of the eastern part of Czecho-Slovakia (as Czechoslovakia had been renamed in October 1938). During the talks, a clash of interests arose between the Italians who favored seeing Hungary restored to pre-Trianon borders, whereas the Germans, who were disappointed over Hungary’s lukewarm attitude towards attacking Czechoslovakia in September 1938, tended to favor Czecho-Slovakia. At the same time, Ribbentrop, who was trying to enlist Italy into his anti-British alliance, was not inclined towards pushing the Italians too hard, and the resulting Vienna Award was a compromise between the rival German and Italian claims to influence in Eastern Europe.

In the aftermath of the Kristallnacht pogrom in November 1938, the U.S. government formally protested and withdrew Hugh Wilson, the American Ambassador in Berlin in protest. In retaliation, Ribbentrop withdrew the German Ambassador in Washington, Hans-Heinrich Dieckhoff, and delivered a counter-protest note accusing the U.S. government of being secretly controlled by Jewish plutocrats. Right up until 1941, German-American relations were conducted by chargé d'affaires as neither government ever sent back their ambassadors.

In regards to the anti-Semitic policies, Ribbentrop emerged as one of the leading hardliners, and refused to even consider the idea (which some of the other Nazi leaders were open to, through only on pragmatic grounds as a way of encouraging Jewish emigration) that German Jews be allowed to bring their personal possessions with them when they left Germany. At a meeting in Paris with the French Foreign Minister, Georges Bonnet in December 1938, when Bonnet asked if it was possible for immigrating German Jews to bring their personal belongings with them, Ribbentrop replied:

"The Jews in Germany were without exception pickpockets, murderers and thieves. The property they possessed had been acquired illegally. The German government had therefore decided to assimilate them with the criminal elements of the population. The property which they had acquired illegally would be taken from them. They would be forced to live in districts frequented by the criminal classes. They would be under police observation like other criminals. They would be forced to report to the police as other criminals were obligated to do. The German government could not help it if some of these criminals escaped to other countries which seemed so anxious to have them. It was not, however, willing for them to take the property, which had resulted from their illegal operations with them".

On 6 December 1938 Ribbentrop visited Paris, where he and the French foreign minister Georges Bonnet signed a grand-sounding but largely meaningless Declaration of Franco-German Friendship. Ribbentrop was later to claim that Bonnet told him that France recognized Eastern Europe as being within Germany's exclusive sphere of influence. Later in December 1938, Ribbentrop, during a meeting with the Polish Foreign Minister Colonel Beck at Berchtesgaden, attempted to win his acceptance of the German proposals by promising him German support for Polish annexation of the Ukraine, only to be told that Poland had no interest in seeing either Danzig return to the Reich, or in annexing the Ukraine. On 6 February 1939, in response to a speech given by Bonnet before the Chamber of Deputies, underlining French commitments in Eastern Europe, Ribbentrop offered a formal protest to Robert Coulondre, the French Ambassador in Berlin, arguing that because of Bonnet’s alleged statement of 6 December 1938, that “France’s commitments in Eastern Europe” were now “off limits”.

Partly for economic reasons, and partly out of fury over being “cheated” out of war in 1938, in early 1939, Hitler decided to commence the destruction of the rump state of Czecho-Slovakia (as Czechoslovakia had been renamed in October 1938). Ribbentrop played an important role in setting the crisis that was to result in the end of Czecho-Slovakia in motion by ordering German diplomats in Bratislava to contact Father Jozef Tiso, the Premier of the Slovak regional government, and pressuring him to declare independence from Prague. When Tiso proved reluctant to do so under the grounds that the autonomy that had existed since October 1938 was sufficient for him, and to completely sever links with the Czechs would leave Slovakia open to being annexed by Hungary, Ribbentrop had the German Embassy in Budapest contact the Regent, Admiral Miklós Horthy. Admiral Horthy was advised that the Germans might be open to having more of Hungary restored to former borders, and that the Hungarians should best start concentrating troops on their northern border at once if they were serious about changing the frontiers. Upon hearing of the Hungarian mobilization, Tiso was presented with the choice of either declaring independence with the understanding that the new state would be in the German sphere of influence, or seeing all of Slovakia absorbed into Hungary. When as a result, Tiso had the Slovak regional government issue a declaration of independence on 14 March 1939, the ensuing crisis in Czech-Slovak relations was used as a pretext to summon the Czecho-Slovak President Emil Hácha to Berlin over his “failure” to keep order in his country. On the night of 14–15 March 1939, Ribbentrop played a key role in the German annexation of the Czech part of Czecho-Slovakia by bullying the Czechoslovak President Hácha into transforming his country into a German protectorate at a meeting in the Reich Chancellery in Berlin. On 15 March 1939, German troops occupied the Czech area of Czecho-Slovakia, which then became the Reich Protectorate of Bohemia and Moravia. On March 20, 1939 Ribbentrop summorned the Lithuanian Foreign Minister Juozas Urbšys to Berlin and informed him that if a Lithuanian plenipoteiary did not arrive at once to negotiate turning over the Memelland to Germany the Luffwaffe would raze Kaunas to the ground. As a result of Ribbentrop's ultimatum on March 23rd, the Lithuanians argeed to return Memel (modern Klaipėda, Lithuania) to Germany.

In March 1939, Ribbentrop assigned the largely ethnic Ukrainian Sub-Carpathian Ruthenia region of Czecho-Slovakia, which had just proclaimed its independence as the Republic of Carpatho-Ukraine to Hungary, which then proceeded to annex it after a short war. The significance of this lies in that there had been many fears in the Soviet Union in the 1930s that the Germans would use Ukrainian nationalism as a tool for breaking up the Soviet Union. The establishment of an autonomous Ukrainian region in Czecho-Slovakia in October 1938 had promoted a major Soviet media campaign against its existence under the grounds that this was part of a Western plot to support separatism in the Soviet Ukraine. By allowing the Hungarians to destroy Europe’s only Ukrainian state, Ribbentrop had signified that Germany was not interested (at least for the moment) in sponsoring Ukrainian nationalism. This in turn helped to improve German-Soviet relations by demonstrating that German foreign policy was now primarily anti-Western rather than anti-Soviet.

Initially, the German hope was to transform Poland into a satellite state, but by March 1939 the German demands had been rejected by the Poles three times, which led Hitler to decide with enthusiastic support from Ribbentrop upon the destruction of Poland as the main German foreign policy goal of 1939. On March 21, 1939 Ribbentrop presented a set of demands to the Polish Ambassador Józef Lipski about Poland allowing the Free City of Danzig to return to Germany in such violent and extreme language that it led to the Poles to fear their country was on the verge of an immediate German attack. Ribbentrop had used such extreme language that it led to the Poles ordering partial Mobilization and placing their armed forces on the highest state of alert on March 23rd, 1939. In a protest note at Ribbentrop’s behaviour, Colonel Beck reminded the German Foreign Minister that Poland was an independent country and was not some sort of German protectorate whom Ribbentrop could bully at will. Though the Germans were not planning an attack on Poland in March 1939, Ribbentrop's bullying behavior towards the Poles destroyed whatever faint chance there was of Poland allowing Danzig to return to Germany.

From March 1939, Ribbentrop had become the leading advocate within the German government of reaching an understanding with the Soviet Union as the best way of pursuing both the short-term anti-Polish, and long-term anti-British foreign policy goals. Ribbentrop's efforts to convert the Anti-Comintern Pact into an anti-British alliance met with considerable hostility from the Japanese over the course of the winter of 1938-39, but with the Italians Ribbentrop enjoyed some apparent success. Because of Japanese opposition to participation in an anti-British alliance, Ribbentrop decided to settle for a bilateral German-Italian anti-British treaty. Ribbentrop's efforts were crowned with success with the signing of the Pact of Steel in May 1939, through this was accomplished only by falsely assuring Mussolini that there would be no war for the next three years.

In April 1939, Ribbentrop received intelligence that Britain and Turkey were negotiating an alliance intended to keep Germany out of the Balkans. Ribbentrop appointed Franz von Papen as the German Ambassador in Ankara with instructions to win Turkey to an alliance with Germany. Instead of focusing on talking to the Turks, Ribbentrop and Papen became entangled in a feud over Papen's demand that he by-pass Ribbentrop and send his dispatches straight to Hitler. At the same time, Ribbentrop took to shouting at the Turkish Ambassador in Berlin Mehmet Hamdi Arpag as part of the effort to win Turkey over as a German ally (Ribbentrop believed that Turks were so stupid that only by shouting at them could one make them understand). One of the consequences of Ribbentrop's heavy-handed behavior was the signing of the Anglo-Turkish alliance of May 12, 1939.

Ribbentrop played a key role in the conclusion of the Soviet-German non-aggression pact, the Molotov - Ribbentrop Pact in 1939, and in the diplomatic action surrounding the attack on Poland. In public, Ribbentrop expressed great fury at the Polish refusal to allow for Danzig's return to the Reich or Polish permission for the “extra-territorial” highways, but since these matters were only intended after March 1939 to be a pretext for German aggression, Ribbentrop always refused in private to allow for any talks between German and Polish diplomats about these matters. It was Ribbentrop's fear that if German-Polish talks did take place, there was the danger that the Poles would agree to the German demands, and thereby deprive the Germans of their excuse for aggression. To further block German-Polish diplomatic talks, Ribbentrop had the German Ambassador to Poland Count Hans-Adolf von Moltke recalled, and refused to see the Polish Ambassador Józef Lipski. Throughout 1939, in private Hitler always described Britain as his main opponent, and portrayed the coming destruction of Poland as a necessary prelude towards the goal of destroying Britain. A notable contradiction existed in Hitler’s strategic planning between embarking on an anti-British foreign policy, whose major instruments consisted of a vastly expanded Kriegsmarine and a Luftwaffe capable of a strategic bombing offensive that would take several years to build (e.g. Plan Z for expanding the Kriegsmarine was a five year plan), and engaging in reckless short-term actions such as attacking Poland that were likely to cause a general war. Ribbentrop, for his part, because of his status as the Nazi British expert, resolved Hitler’s dilemma by supporting the anti-British line and by repeatedly advising Hitler that Britain would not go to war for Poland in 1939. Ribbentrop informed Hitler that any war with Poland would last for only 24 hours, and that the British would be so stunned with this display of German power that they would not honor their commitments. Ribbentrop supported his analysis of the situation by only showing Hitler diplomatic dispatches that supported his view that neither Britain or France would honor their commitments to Poland. In this, Ribbentrop was particularly supported by the German Ambassador in London, Herbert von Dirksen who reported that Chamberlain knew “the social structure of Britain, even the conception of the British Empire, would not survive the chaos of even a victorious war”, and so would back down over Poland. Furthermore, Ribbentrop had the German Embassy in London provide translations from pro-appeasement newspapers like the Daily Mail and the Daily Express for Hitler's benefit, which had the effect of making it seem that British public opinion was more strongly against going to war for Poland than was actually the case. The British historian Victor Rothwell wrote that the newspapers such as the Daily Express and the Daily Mail that Ribbentrop used to provide his press summaries for Hitler were out of touch not only with British public opinion, but also British government policy in regards to Poland. The press summaries Ribbentrop provided were particularly important as Ribbentrop had managed to convince Hitler that the British government secretly controlled the British press, and just as in Germany, nothing appeared in the British press that the British government did not want to appear. During the summer of 1939, Ribbentrop sabotaged all efforts at a peaceful solution to the Danzig dispute, leading the American historian Gerhard Weinberg to comment that “perhaps Chamberlain’s haggard appearance did him more credit than Ribbentrop’s beaming smile” as the countdown to a war that would kill millions inexorably gathered pace.

In June 1939, Franco-German relations were strained when the head of the French section of the Dienststelle Ribbentrop, Otto Abetz was expelled from France following allegations that he had bribed two French newspaper editors to print pro-German articles. Ribbentrop was enraged by Abetz's expulsion, and attacked Count Johannes von Welczeck, the German Ambassador in Paris over his failure to have the French re-admit Abetz. In July 1939, Ribbentrop's claims about Bonnet's alleged statement of December 1938 was to lead to a lengthy war of words via a series of letters to the French newspapers between Bonnet and Ribbentrop over just what precisely Bonnet said to Ribbentrop. In the spring and summer of 1939, Ribbentrop used Bonnet's alleged statement to convince Hitler that France would not go to war in the defense of Poland, despite the frequent denials by Bonnet that he ever made such a statement (which would not have been legally binding even had Bonnet had made the alleged statement).

The signing of the Non-Aggression Pact in Moscow on 23 August 1939 was the crowning achievement of Ribbentrop's career. Ribbentrop flew to Moscow, where over the course of a thirteen hour visit, Ribbentrop signed both the Non-Aggression Pact and the secret protocols, which partitioned much of Eastern Europe between the Soviets and the Germans. Ribbentrop had only expected to see the Soviet Foreign Commissar Vyacheslav Molotov, and was most surprised to be holding talks with Joseph Stalin. During his trip to Moscow, Ribbentrop's talks with the Stalin and Molotov proceeded very cordially and efficiently with the exception of the question of Latvia, which Hitler had instructed Ribbentrop to try and claim for Germany. When Stalin claimed Latvia for the Soviet Union, Ribbentrop was forced to telephone Berlin for permission from Hitler to concede Latvia to the Soviets. After finishing his talks with Stalin and Molotov, Ribbentrop at a dinner with the Soviet leaders launched a lengthy diatribe against the British Empire with frequent injunctions of approval from Stalin, and then exchanged toasts with Stalin in honor of German-Soviet friendship. For a brief moment in August 1939, Ribbentrop convinced Hitler that the Non-Aggression Pact with the Soviet Union would cause the fall of the Chamberlain government, and lead to a new British government that would abandon the Poles to their fate. Ribbentrop argued that with Soviet economic support (especially in the form of oil), Germany was now immune to the effects of a British naval blockade, and as such, the British would never take on Germany. Unlike Hitler who saw the Non-Aggression Pact as merely a pragmatic device forced on him by circumstances, namely the refusal of Britain or Poland to play the roles Hitler had allocated to them, Ribbentrop regarded the Non-Aggression Pact as integral to his anti-British policy.

On August 27, 1939 Chamberlain sent the following letter to Hitler intended to counter-act reports Chamberlain had heard from intelligence sources in Berlin that Ribbentrop had convinced Hitler that the Molotov - Ribbentrop Pact would ensure that Britain would abandon Poland. In his letter to Hitler, Chamberlain wrote:

“Whatever may prove to be the nature of the German-Soviet Agreement, it cannot alter Great Britain’s obligation to Poland which His Majesty’s Government have stated in public repeatedly and plainly and which they are determined to fulfill. It has been alleged that, if His Majesty’s Government had made their position more clear in 1914, the great catastrophe would have been avoided. Whether or not there is any force in that allegation, His Majesty’s Government are resolved that on this occasion there shall be no such tragic misunderstanding. If the case should arise, they are resolved, and prepared, to employ without delay all the forces at their command, and it is impossible to foresee the end of hostilities once engaged. It would be a dangerous illusion to think that, if war once starts, it will come to an early end even if a success on any one of the several fronts on which it will be engaged should have been secured”

Ribbentrop for his part told Hitler that Chamberlain's letter was just a bluff, and urged his master to call it.

On the night of 30–31 August 1939, Ribbentrop had an extremely heated interview with the British Ambassador Sir Nevile Henderson, who objected to Ribbentrop's demand given at about midnight that if a Polish plenipotentiary did not arrive in Berlin that night to discuss the German "final offer", then the responsibility for the outbreak of war would not rest on the Reich. Henderson argued that the terms of the German "final offer" were very reasonable, but argued that Ribbentrop's time limit for Polish acceptance of the "final offer" was most unreasonable, and furthermore, demanded to know why Ribbentrop insisted upon seeing a special Polish plenipotentiary and could not present the "final offer" to Józef Lipski or provide a written copy of the "final offer". The Henderson - Ribbentrop meeting became so tense that the two men almost came to blows. The American historian Gerhard Weinberg described the Henderson - Ribbentrop meeting as:

"When Joachim Von Ribbentrop refused to give a copy of the German demands to the British Ambassador [Henderson] at midnight of 30 August - 31 August 1939, the two almost came to blows. Ambassador Henderson, who had long advocated concessions to Germany, recognized that here was a deliberately conceived alibi the German government had prepared for a war it was determined to start. No wonder Henderson was angry; von Ribbentrop on the other hand could see war ahead and went home beaming."

As intended by Ribbentrop, the narrow time limit for acceptance of the "final offer" made it impossible for the British government to contact the Polish government in time about the German offer, let alone for the Poles to arrange for a Polish plenipotentiary envoy to arrive in Berlin that night, thereby allowing Ribbentrop to claim that the Poles had rejected the German "final offer". The "rejection" of the German proposal was one of the pretexts used for the German aggression against Poland on 1 September 1939.

When on the morning of 3 September 1939 Chamberlain followed through with his threat of a British declaration of war if Germany attacked Poland, a visibly shocked Hitler asked Ribbentrop “Now what?”, a question to which Ribbentrop had no answer except to state that there would be a "similar message" forthcoming from the French Ambassador Robert Coulondre, who arrived later that afternoon to present the French declaration of war. In part due to Ribbentrop’s influence, it has been often observed that Hitler went to war in 1939 with the country he wanted as his ally — namely the United Kingdom — as his enemy, and the country he wanted as his enemy — namely the Soviet Union — as his ally.

After the outbreak of World War II, Ribbentrop spent most of the Polish campaign traveling with Hitler. On 27 September 1939, Ribbentrop made a second visit to Moscow, where at meetings with the Soviet Foreign Commissar Vyacheslav Molotov and Joseph Stalin, he was forced to agree to revising the Secret Protocols of the Non-Aggression Pact in the Soviet Union's favor, most notably agreeing to Stalin’s demand that Lithuania go to the Soviet Union. The imposition of the British blockade had made the Reich highly dependent upon Soviet economic support, which placed Stalin in a strong negotiating position with Ribbentrop. On 1 March 1940, Ribbentrop received Sumner Welles, the American Under-Secretary of State, who was on a peace mission for President Franklin D. Roosevelt, and did his best to abuse his American guest. On 7 May 1940, Ribbentrop founded a new section of the Auswärtiges Amt, the Abteilung Deutschland (Department of Internal German Affairs) under Martin Luther, to which was assigned the responsibility for all anti-Semitic affairs.

With his appointment as Foreign Minister, Ribbentrop became more abrasive and arrogant. On May 19, 1940 Ribbentrop met the new Italian Ambassador Dino Alfieri, who described the meeting as follows:

"He commented at length on the "dazzling" successes of the German armies, extolling the military genius of the Führer... who had "revealed himself as the greatest military genius since Napoleon"... He spoke of the inevitable clash between the young nations and the old; of the necessity of breaking the ring with which the Judaedo-democratic-plutocratic powers were trying to encircle Germany and Italy; and of the need to create a new European civilization. What he said was neither new, remarkable, nor particulary interesting... He talked for more than an hour in a voice which never varied in tone, resting one hand in palm of the other and periodically glancing at his fingernails... He insisted on my remaining for lunch. The food and wine were excellent, but the conversation tedious to a degree. Afterwards, he suggested we go into the garden. There he repeated in a different form all that he had already said, for all the world as if he had a gramophone fixed in his brain... When I took leave, he subjected me to an interminable handshake, meanwhile fixing his cold blue eyes on mine, and repeating almost word for word what he said to me on arrival... I felt I should never be able to establish any human contact with this man"

After June 1940, Ribbentrop, who was a Francophile, argued that Germany should allow Vichy France a limited degree of independence within a binding new Franco-German partnership. To this end, Ribbentrop appointed a colleague from the Dienststelle named Otto Abetz as Ambassador to France with instructions to promote the political career of Pierre Laval, whom Ribbentrop had decided was the French politician most favorable to Germany. The amount of Auswärtiges Amt influence in France varied as there were many other agencies competing for power there such as the military, the SS and the Four Year Plan office of Ribbentrop's archenemy Hermann Göring, but in general from late 1943 to mid-1944, the Auswärtiges Amt was second only to the SS in terms of power in France.

From the later half of 1937, Ribbentrop had championed the idea of an alliance between Germany, Italy and Japan that would partition the British Empire between them. After signing the Soviet-German Non-Aggression Pact, Ribbentrop expanded on this idea for an Axis alliance to include the Soviet Union to form an Eurasian bloc that would destroy maritime states such as Britain. The German historian Klaus Hildebrand argued that besides Hitler’s foreign policy programme, there were three other factions within the Nazi Party who had alternative foreign policy programmes, whom Hildebrand dubbed the agrarians, the revolutionary socialists, and the Wilhelmine Imperialists. Another German diplomatic historian, Wolfgang Michalka argued that there was a fourth alternative Nazi foreign policy programme, and that was Ribbentrop’s concept of a Euro-Asiatic bloc comprising the four totalitarian states of Germany, the Soviet Union, Italy and Japan. Unlike the other factions, Ribbentrop’s foreign policy programme was the only one that Hitler allowed to be executed during the years 1939-41, though it was more due to the temporary bankruptcy of Hitler’s own foreign policy programme that he had laid in Mein Kampf and Zweites Buch following the failure to achieve an alliance with Britain, than to a genuine change of mind. Ribbentrop's foreign policy conceptions differed from Hitler's in that Ribbentrop's concept of international relations owed more to the traditional Wilhelmine Machtpolitik than to Hitler's racist and Social Darwinist vision of different "races" locked in a merciless and endless struggle over Lebensraum. The different foreign-policy conceptions held by Hitler and Ribbentrop were illustrated in their reaction to the Fall of Singapore in 1942: Ribbentrop wanted this great British defeat to be a day of celebration in Germany, whereas Hitler forbade any celebrations on the grounds that Singapore represented a sad day for the principles of white supremacy. Another area of difference was that Ribbentrop had an obsessive hatred for Britain — which he saw as the main enemy — and the Soviet Union as important ally in the anti-British struggle; whereas Hitler saw the alliance with the Soviet Union as only tactical, and was nowhere as anti-British as his Foreign Minister. Ribbentrop liked and admired Stalin, and was against the attack on the USSR in 1941. He passed a word to a Soviet diplomat: "Please tell Stalin I was against this war, and that I know it will bring great misfortune to Germany."

In the fall of 1940, Ribbentrop made a sustained but unsuccessful effort to have Spain enter the war on the Axis side. During his talks with the Spanish foreign minister, Ramón Serrano Súñer, Ribbentrop affronted Súñer with his tactless behavior, especially his suggestion that Spain cede the Canary Islands to Germany. An angry Súñer replied that he would rather see the Canaries sink into the Atlantic than cede an inch of Spanish territory. Another area where Ribbentrop enjoyed more success occurred in September 1940, when he had the Far Eastern agent of the Dienststelle Ribbentrop, Dr. Heinrich Georg Stahmer, start negotiations with the Japanese foreign minister, Yosuke Matsuoka, for an anti-American alliance (the German Ambassador to Japan, General Eugen Ott, was excluded from the talks on Ribbentrop's orders). The end result of these talks was the signing in Berlin of the Tripartite Pact by Ribbentrop, Count Ciano, and the Japanese Ambassador Saburo Kurusu. It was Ribbentrop's hope that the prospect of facing the Tripartite Pact would deter the United States from supporting Britain, but since the Pact was more or less openly directed against the United States (the Pact made a point of stressing that the unnamed great power it was directed against was not the Soviet Union), it had the opposite effect on American public opinion, to the one intended.

In November 1940, during the visit of the Soviet Foreign Commissar Vyacheslav Molotov to Berlin, Ribbentrop tried hard to get the Soviet Union to sign the Tripartite Pact. Ribbentrop argued that the Soviets and Germans shared a common enemy in the form of the British Empire, and as such, it was in the best interests of the Kremlin to enter the war on the Axis side. Ribbentrop presented a proposal to Molotov where after the defeat of Britain, the Soviet Union would have India and the Middle East, Italy the Mediterranean area, Japan the British possessions in the Far East (presuming of course that Japan would enter the war), and Germany would take Central Africa and Britain itself. Through Molotov was open to the idea of the Soviet Union entering the war on the Axis side, but demanded as the price of Soviet entry into the war that Finland, Bulgaria, Romania, Turkey, Hungary and Yugoslavia be recognised as in the exclusive Soviet sphere of influence. Ribbentrop’s efforts to persuade Molotov to abandon his demands about Europe as the price of Soviet entry into the war as a German ally were entirely unsuccessful.

In the winter of 1940-41, Ribbentrop strongly pressured Yugoslavia to sign the Tripartite Pact, despite advice from the German Legation in Belgrade that such a move would probably lead to the overthrow of Crown Prince Paul, the Yugoslav Regent. On March 25, 1941, Yugoslavia signed the Tripartite Pact, which led to the overthrow of Prince Paul the next day. When Hitler ordered Yugoslavia to be invaded, Ribbentrop was opposed, through only because the Auswärtiges Amt was likely to be excluded from ruling the occupied Yugoslavia. As Hitler was displeased with Ribbentrop over his opposition to attacking Yugoslavia, he then broke down and took to his bed for the next couple of days. When Ribbentrop recovered, he sought a chance for increasing Auswärtiges Amt influence by having Croatia being given independence. Ribbentrop chose the Ustaša to rule Croatia, and had Edmund Veesenmayer of the Auswärtiges Amt successfully conclude talks in April 1941 with General Slavko Kvaternik of the Ustaša on having his party rule Croatia after the German invasion. Reflecting his displeasure with the German Legation in Belgrade, which had adviced against pressuring Yugoslavia into signing the Tripartite Pact, when the Bombing of Belgrade took place on April 6, 1941, Ribbentrop refused to have the staff of the German Legation withdrawn in advance, who were thus left to survive the fire-bombing of Belgrade as best they could.

In the spring of 1941, Ribbentrop strongly pushed for German aid to for the Rashid Ali al-Gaylani government in Iraq, where he saw a great opportunity of striking a blow at British influence in the Middle East. It was Ribbentrop's hope that a striking German success in Iraq might lead to Hitler abandoning his plans for Operation Barbarossa, and focusing instead on the struggle with Britain. The abject failure of Ribbentrop's Iraq scheme in May 1941 had the effect totally opposite to the one intended.

Ribbentrop was found to have had culpability in the Holocaust on the grounds that he persuaded the leaders of satellite countries of the Third Reich to deport Jews to the Nazi extermination camps. He championed the so-called Madagascar Plan in June 1940 to deport all of Europe's Jews to Madagascar after the presumed imminent defeat of Britain. As World War II went on, Ribbentrop's once friendly relations with the SS became increasingly strained. In January 1941, the nadir of SS - Auswärtiges Amt relations was reached when the Iron Guard attempted a coup in Romania, with Ribbentrop supporting the government of Marshal Ion Antonescu and Himmler supporting the Iron Guard. In the aftermath of the failed coup in Bucharest, the Auswärtiges Amt assembled evidence that the SD had backed the coup, which led to Ribbentrop sharply restricting the powers of the SD police attachés, who since October 1939 had operated largely independently of the German embassies at which they had been stationed. In the spring of 1941, Ribbentrop appointed an assemblage of SA men to German embassies in Eastern Europe, with Manfred von Killinger going to Romania, Siegfried Kasche to Croatia, Adolf Beckerle to Bulgaria, Dietrich von Jagow to Hungary, and Hans Ludin to Slovakia. The major qualifications of all these men, none of whom had previously held a diplomatic position before, were that they were close friends of Luther, and as a way of splitting the SS (the traditional rivalry between the SS and SA was still running strong).

Despite his opposition to Operation Barbarossa and a preference for focusing the war effort against Britain, on June 28, 1941, Ribbentrop began a sustained effort to have Japan attack the Soviet Union. However, Ribbentrop's motives in seeking to have Japan enter the war were more anti-British then anti-Soviet. On July 10, 1941 Ribbentrop ordered General Eugen Ott, the German Ambassador to Japan to:

"Go on with your efforts to bring about the earliest possible participation of Japan in the war against Russia... The natural goal must be, as before, to bring about the meeting of Germany and Japan on the Trans-Siberiain Railroad before winter sets in. With the collapse of Russia, the position of the Tripartite Powers in the world will be so gigantic that the question of the collapse of England, that is, the absolute annihilation of the British Isles, will only be a question of time. An America completely isolated from the rest of the world would then be faced with the seizure of those of the remaining positions of the British Empire important to the Tripartite Powers".

As part of his efforts to bring Japan into Barbarossa, on July 1, 1941, Ribbentrop had Germany break off diplomatic relations with Chiang Kai-shek and instead recognized the Japanese puppet government of Wang Jingwei as the legitimate government of China. In addition, Ribbentrop hoped that recognizing Wang would be seen as a coup which might add to the prestige of the pro-German Japanese Foreign Minister Yosuke Matsuoka, who was opposed to opening American - Japanese talks. Despite Ribbentrop's best efforts, Matsuoka was sacked as Foreign Minister later in July 1941, and the Japanese - American talks began.

In August 1941, when the question of whether to deport foreign Jews living in Germany arose, Ribbentrop argued against deportation as a way of maximizing the influence of the Auswärtiges Amt. In order to deport foreign Jews living in the Reich, Ribbentrop then had Luther negotiate agreements with the governments of Romania, Slovakia and Croatia to allow Jews holding citizenships of those states to be deported. In September 1941, the Reich Plenipotentiary for Serbia, Felix Benzler of Auswärtiges Amt, reported to Ribbentrop that the SS had arrested 8,000 Serbian Jews, whom they were planning to execute en masse, and asked for permission to try to stop the massacre. Ribbentrop assigned the question to Luther, who in turn ordered Benzler to co-operate fully in the massacre.

In the fall of 1941, Ribbentrop worked for both the failure of the Japanese - American talks in Washington and Japan attacking the United States. In October 1941 Ribbentrop ordered General Ott to start applying pressure on the Japanese to attack the Americans as soon as possible. Ribbentrop argued to Hitler that a war between the United States and Germany was inevitable given the extent of American aid to Britain and the increasingly frequent "incidents" in the North Atlantic between U-boats and American warships guarding convoys to Britain, and that having such a war begin with a Japanese attack on the United States was the best way to begin it. Ribbentrop told Hitler that because of his four years in Canada, he was an expert on all things American, and that the United States in his opinion was not a serious military power. On December 4, 1941, the Japanese Ambassador General Hiroshi Ōshima told Ribbentrop that Japan was on the verge of war with the United States, which led to Ribbentrop promising him on behalf of Hitler that Germany would join the war against the Americans. On December 7, 1941 Ribbentrop was jubilant at the news of Pearl Harbour, and did his utmost to support declaring war on the United States, which was duly delivered on December 11, 1941.

In April 1942, Ribbentrop had assembled in Hotel Adlon in Berlin a collection of anti-Soviet émigrés from the Caucasus with the aim of having them declared leaders of governments in exile. From Ribbentrop's point of view, this had the dual benefit of ensuring popular support for the German Army as it advanced into the Caucasus and of ensuring that it was the Auswärtiges Amt that ruled the Caucasus once the Germans occupied the area. Alfred Rosenberg, the German Minister of the East, saw this as an intrusion into his area of authority, and told Hitler that the émigrés at the Hotel Adlon were "a nest of Allied agents". Much to Ribbentrop's intense disappointment, Hitler sided with Rosenberg. For Hitler, the Soviet Union was to be Germany's Lebensraum and he had no interest in even setting up puppet governments in a region he planned to colonize.

Despite the often fierce rivalry with the SS, the Auswärtiges Amt played a key role in arranging the deportations of Jews to the death camps from France (1942–44), Hungary (1944–45), Slovakia, Italy (after 1943), and the Balkans. Ribbentrop assigned all of the Holocaust - related work to an old crony from the Dienststelle named Martin Luther, who represented the Foreign Ministry at the Wannsee Conference. In 1942, Ambassador Otto Abetz secured the deportation of 25,000 French Jews, and Ambassador Hans Ludin secured the deportation of 50,000 Slovak Jews to the death camps. Only once, in August 1942, did Ribbentrop attempt to impede the deportations, but only because of jurisdictional disputes with the SS. Ribbentrop ordered the halt of deportations from Romania and Croatia: In the case of the former, he was insulted because the SS were negotiating with the Romanians directly, and in the case of the latter because the SS and Luther were jointly pressuring the Italians in their zone of occupation in Croatia to deport their Jews without informing Ribbentrop first, who was supposed to be personally kept abreast of all developments in Italo-German relations. In September 1942, after a meeting with Hitler, who was most unhappy with his Foreign Minister's actions, Ribbentrop promptly changed course and ordered that the deportations be resumed at once with all speed.

Another low point in Ribbentrop's relations with the SS occurred in February 1943, when the SD backed an internal putsch attempt by Luther to oust Ribbentrop as Foreign Minister. Luther had become estranged from Ribbentrop because he continued to be treated as a household servant by Frau Ribbentrop, who, in turn, had pressured her husband into ordering an investigation into allegations of corruption on Luther’s part. The putsch failed largely because at the last minute Himmler decided that a Foreign Ministry headed by Luther would be a more dangerous opponent than one by Ribbentrop, and so withdrew his support from Luther. In the aftermath of the failed putsch, Luther was sent to Sachsenhausen concentration camp.

As the war went on, Ribbentrop's influence declined. Since much of the world was at war with Germany, which was losing, the usefulness of the Foreign Ministry became increasingly limited. Hitler, for his part, found Ribbentrop increasingly tiresome, and sought to avoid him. The Foreign Minister's ever more desperate pleas for Hitler to allow him to find some way of making peace with at least some of Germany's enemies — the Soviet Union in particular — certainly played a role in this estrangement. In September 1943, the German Embassy in Stockholm came into contact with a NKVD agent who offered on behalf of the Soviet Union to start German - Soviet peace talks. Ribbentrop very much favored taking up the Soviet peace feeler, only to be overruled by Hitler, who had no interest in the Soviet peace offer. As Ribbentrop's influence with Hitler went into a sharp decline after 1943, he increasingly spent his time feuding with other Nazi leaders over control of anti-Semitic policies as a way of trying to win back Hitler's favor. In December 1943, Ribbentrop played a key role in having the radical French fascists installed into key positions in the Vichy cabinet. Ribbentrop had Joseph Darnand appointed as Interior Minister, Marcel Déat as Labour Minister and Philippe Henriot as Information Minister. One of Ribbentrop's last significant acts in the field of foreign relations was his role in the Ryti - Ribbentrop Agreement with Finnish President Risto Ryti.

In the spring of 1944, the German Reich Plenipotentiary for Hungary, Edmund Veesenmayer (formally Ribbentrop’s liaison man with the IRA) of the Auswärtiges Amt played a major role in helping to arrange the deportation of 400,000 Hungarian Jews to the death camps. Veesenmayer kept Ribbentrop fully informed about the Hungarian deportations, sending the Foreign Minister weekly reports about the deportations, and threatened the Hungarian Regent, Admiral Miklós Horthy, when he ordered a halt to the deportations in July 1944. On 28 April 1944, Ribbentrop, who had finally won control of foreign propaganda, founded a new section at the Auswärtiges Amt called "Anti-Jewish Action Abroad" under Rudolf Schleier, which included Mohammad Amin al-Husayni and Rashid Ali al-Gaylani as members, and was given the responsibility of conducting anti-Semitic propaganda abroad.

A major blow against Ribbentrop was the participation of many old diplomats from the Auswärtige Amt in the 20 July 1944 putsch and assassination attempt against Hitler. Ribbentrop had no knowledge of the plot, but the involvement of so many former and serving members of the Foreign Ministry reflected badly on him. Hitler felt with some justification that Ribbentrop was not keeping proper tabs on what his diplomats were up to, because of his "bloated administration". After 20 July, Ribbentrop worked closely with the SS, with whom by this time he was reconciled, in purging the Auswärtige Amt of those suspected of involvement with the putsch. Two of the more notable diplomats to be executed after the July putsch were Count Friedrich Werner von der Schulenburg and Ulrich von Hassell. As part of the purge effort, and at the instigation of his wife, Ribbentrop had Lieny Behlau, the widow of Frau Ribbentrop's younger brother, sent to a concentration camp in August 1944 under the Sippenhaft law, and the custody of her two children assigned to himself and his wife, which had the benefit of making the Ribbentrops the legal guardians of Behlau's share of the Henkell family fortune. Ribbentrop worked in close co-operation with the SS for what turned out to be his last significant foreign policy move, Operation Panzerfaust, the coup that deposed Admiral Miklós Horthy, the Regent of Hungary, on 15 October 1944. Horthy was deposed because he attempted to seek a separate peace with the Allies, and was replaced with Ferenc Szálasi, who resumed the deportation of Hungarian Jews in co-operation with the SS and the Auswärtige Amt that Horthy had halted in July 1944.

On 20 April 1945, Ribbentrop attended Hitler's 56th birthday party in Berlin. This was one of the last times he saw Hitler. On 23 April 1945, Ribbentrop attempted to have a meeting with Hitler, only to be told to go away, as Hitler had more important things to do than talk to him. This was his last meeting with Hitler.

On 14 June 1945, Ribbentrop was arrested by Sergeant Jacques Goffinet, a French citizen who had joined the Belgian SAS and was working with British forces near Hamburg. Found with him was a rambling letter addressed to the British Prime Minister "Vincent Churchill" criticizing British foreign policy for anti-German bias, blaming the British for the Soviet occupation of the eastern half of Germany, and thus for the advance of "Bolshevism" into central Europe. The fact that Ribbentrop even in 1945 did not record that Churchill's first name was "Winston" reflected either his general ignorance about the world outside of Germany, or else a distracted state of mind at the time of writing the letter.

Ribbentrop was a defendant at the Nuremberg Trials, charged with crimes against peace, deliberately planning a war of aggression, war crimes and crimes against humanity. Prosecutors presented evidence that Ribbentrop was actively involved in the planning of German aggression and the deportation of Jews to death camps, as well as his advocacy of the killing of American and British airmen shot down over Germany. The Allies' International Military Tribunal found him guilty of all charges brought against him. Even in prison, Ribbentrop remained subservient to Hitler, stating "Even with all I know, if in this cell Hitler should come to me and say 'Do this!', I would still do it." During the trial, Ribbentrop rather unsuccessfully attempted to deny his role in the war. For example, during his cross-examination, the prosecution brought up claims that he (along with Hitler and Göring) threatened the Czechoslovak President Emil Hácha in March 1939, with a "threat of aggressive action". The questioning resulted in the following exchange between the British Prosecutor Sir David Maxwell-Fyfe and Ribbentrop:

Maxwell-Fyfe: What further pressure could you put on the head of a country beyond threatening him that your Army would march in, in overwhelming strength, and your air force would bomb his capital?

Ribbentrop: War, for instance.

While not recorded in the trial transcript, Hermann Göring was said to have remarked, after hearing these words, that Ribbentrop deserved to be hanged, if only for his stupidity.

During the trial, Gustave Gilbert, an American Army psychologist, was allowed to examine the Nazi leaders who were tried at Nuremberg for war crimes. Among other tests, a German version of the Wechsler-Bellevue IQ test was administered. Joachim von Ribbentrop scored 129, the 10th highest among the Nazi leaders tested.

At one point during the trial proceedings, U.S. Army interpreter for the prosecution Richard Sonnenfeldt asked Baron Ernst von Weizsacker, Ribbentrop's second in command, how Hitler could have made him a high official. Weizsacker responded "Hitler never noticed Ribbentrop's babbling because Hitler always did all the talking."

Since Göring had committed suicide a few hours prior to the time of execution, Ribbentrop was the first politician to be hanged on the morning of 16 October 1946. After being escorted up the 13 steps to the waiting noose, Ribbentrop was asked if he had any final words. He calmly said: "God protect Germany. God have mercy on my soul. My final wish is that Germany should recover her unity and that, for the sake of peace, there should be understanding between East and West." As the hood was placed over his head, Ribbentrop added: "I wish peace to the world." After a slight pause the executioner pulled the lever, releasing the trap door Ribbentrop stood upon. His neck snapped, he hung for 17 minutes before the doctor declared him dead. Historian Giles MacDonogh records a very different result: "The hangman botched the execution and the rope throttled the former foreign minister for twenty minutes before he expired."

In 1953 Ribbentrop's memoirs, Zwischen London und Moskau (Between London and Moscow), were published.