Ben Bella volunteered for service in the French Army in 1936. The Army was one of the few avenues of advancement for Algerian Muslims under colonial rule and voluntary enlistment was common. Posted to Marseille he played center mid - field for Olympique de Marseille in 1939 – 1940. He was offered a professional spot on the team, but rejected the offer. He also played for IRB Maghnia.

Ben Bella's eldest brother had also served in the French Army during World War I and died of his wounds. Two other brothers died at young ages. In 1940 Ben Bella enlisted again and was awarded the Croix de guerre . He was demobilized after the fall of France but joined a regiment of Moroccan tirailleurs (infantry) with whom he saw service throughout the Italian campaign. Ben Bella was promoted to the rank of warrant officer and received the Médaille militaire for bravery at Monte Cassino from Charles de Gaulle. He refused to accept an officer's commission after learning of the harsh French repression that followed a Muslim rising in the small Algerian town of Setif in May 1945.

Following election as a municipal councilor Ben Bella became a founder member of an underground organization pledged to fight colonial rule, known as the Organisation Spéciale. This was the immediate predecessor of the Front de Libération Nationale. Arrested in 1951 and sentenced to eight years imprisonment Ben Bella escaped from Blida prison, making his way to Tunisia and then Egypt.

At the outbreak of the Algerian War in 1954 Ben Bella was based in Cairo where he had become one of the nine members of the Revolutionary Committee of Unity and Action which headed the Front de Liberation Nationale (FLN). He was arrested by the French in 1956, after his airplane had been controversially intercepted and brought to France, and released in 1962. His arrest led to the resignation of Alain Savary, opposed to Guy Mollet's policies. While in prison he was elected a vice premier of the Algerian provisional government. Ben Bella's first language was French, not Arabic. He learned Arabic while in prison. While in Egypt, Ben Bella met the Egyptian president, Gamel Abdel Nasser. When Abdel Nasser brought Ben Bella to speak for the first time to an Egyptian audience, he broke into tears because he could not speak Arabic. It has been said that he refused to teach his own daughter French because he wanted her to learn Arabic first and not be in the same position he was. Like many Arab militants of the time, he would come to describe himself as a "Nasserist" and developed close ties to Egypt even before independence was achieved. Abdel Nasser's material, emotional and political support of the Algerian movement would come to cause him troubles, as it played a major role in France's choice to wage war on him during the 1956 Suez Crisis.

Due to Pakistan's support to the cause of Algerian struggle for self determination and independence, Ben Bella was given a Pakistani diplomatic passport to make his foreign travels possible in the face of the international hunt down by the French and their allies. Ben Bella also traveled on a Pakistani diplomatic passport during the years of his exile from Algeria in 1980s.

After Algeria's independence, Ben Bella quickly became more popular. In June 1962, he challenged the leadership of Premier Benyoucef Benkhedda; this led to several disputes among his rivals in the FLN, which were quickly suppressed by Ben Bella's rapidly growing number of supporters, most notably within the armed forces. By September, Bella was in control of Algeria by all but name, and was elected as premier in a one sided election on 20 September, which was recognized by the United States on September 29. Algeria was admitted as the 109th member of the United Nations on 8 October 1962.

In 1963 he was elected President in an uncontested election, and also led Algeria's costly defense against Moroccan invasion in the Sand war. After stabilizing the country, Ben Bella embarked on a series of popular but somewhat anarchic land reforms to the benefit of landless farmers, and increasingly turned to socialist rhetoric. His policy of Autogestion, or self management, was adopted after the peasants seized former French lands. In balancing factions within the Algerian government, notably the FLN army, the former guerrillas and the state bureaucracy, his rule became increasingly autocratic. Eccentric and arrogant behavior towards colleagues is said to have alienated many former supporters, and, while he promoted the development of his own cult of personality, by 1964 he was dedicating more time to foreign affairs than local political developments. In 1965, Ben Bella was deposed by army strongman and close friend Houari Boumédiènne in 1965, and placed under house arrest until 1980, when he was granted exile in Switzerland. He lived for 10 years in Lausanne, but was allowed to return to his homeland in 1990.

Ahmed Ben Bella was awarded the title Hero of the Soviet Union on April 30, 1964.

Ben Bella was elected President of the International Campaign Against Aggression on Iraq at its Cairo Conference. Ben Bella has described himself numerous times in interviews as an Islamist of a mild and peace loving flavor. Despite his former one party state he now vocally advocates democracy in Algeria. He has described the militant voice rising in the Islamic world as having developed from an incorrect and faulty interpretation of Islam. He is a controversial figure, but widely respected for his role in the anti - colonial struggle, and seen by many Arab intellectuals as one of the last original Arab nationalists.

President Ben Bella is currently Chairperson of the African Union Panel of the Wise, which is mandated to advise the AU Commission on issues relevant to conflict prevention, management and resolution. The other members of the Panel are: President Miguel Trovoada (Former President of São Tomé and Príncipe); DR. Salim A. Salim (former Secretary - General of the OAU); Dr. Brigalia Bam (current Chair of South Africa's Electoral Commission); and Mme. Elisabeth Pognon (former President of the Constitutional Court of Benin).