At the age of 16 Batthyány finished his studies at boarding school and attended the Academy in Zágráb (now University of Zagreb, Croatia). In 1826 he took a tour of duty inItaly for four years, where he was promoted to lieutenant and got his law degree. In 1830 he became a hereditary peer in the Upper House in Hungary and took his seat in the Parliament, but at this time Battyhány was not a politician by nature.

In December 1834 he married Antónia Zichy (daughter of Károly Zichy and Antónia Batthyány). Their children were: Amália Batthyány (1837 – 1922), Ilona Batthyány (1842 – 1929) and Elemér Batthyány (1847 – 1932). Batthyány's friend said that Antónia (his wife) encouraged him to take on larger responsibilities in politics.

Batthyány became more involved after the 1839 – 1840 diet in Pozsony and was the Leader of the Opposition. He drew up a reform plan for them. Batthyány advised employing stenographers to record verbatim the proceedings of the Upper House starting in 1840.

Batthyány agreed with István Széchenyi's views on economics and politics. At the beginning of the 1830s Batthyány was one of the people who promoted horse breeding in Hungary. Later they expanded into other animal breeding and established the Association of Hungarian Economy. Batthyány, following Széchenyi, supported breeding silkworms: he planted more than 50,000 mulberry trees on his farm to cultivate them. The Vas shire county and the Economics Association of Szombathely were founded with Batthyány's help.

At the start he agreed with Széchenyi that the new noblemen and aristocrats had to lead the new reform movement, but Batthyány's views were much closer to that of the nobility. Because of this Batthyány tried to bite his tongue when dealing with Széchenyi and Lajos Kossuth. From 1843 onward he started to work with Kossuth. In the 1843 – 1844 parliament Batthány was the Leader of the Opposition for the entire parliament, and criticised the Habsburg Empire's internal affairs and foreign policy.

After the dissolution of parliament Batthyány moved to Pest and in 1845 he was elected as the chairman of the Central Election Office. He had an important role in the other economic associations and set up the Védegylet (roughly: "Defence society" ). On 15 March 1847 an amalgamation of the Hungarian Leftist movements (the Maverick Party) was founded and Batthyány became its first President. Batthyány supported Kossuth both morally and financially. Kossuth became the representative for Pest County in the 1847 diet. After this Batthyány was the Leader of the Opposition in the Upper House while Kossuth had the same role in the Lower House. Batthyány was part of the delegation to the Emperor Ferdinand I of Austria. They insisted Hungary's government be supreme in its territory. On 17 March 1848 the Emperor assented and Batthyány created the first Hungarian Diet. On 23 March 1848, as head of state, Batthyány commended his government to the Diet.

The first task of the government was to work out the revolution's policies. After these were agreed, his government started to act on 11 April 1848. At that time the internal affairs and foreign policy of Hungary were not stable, and Batthyány faced many problems. His first and most important act was to organise the armed forces and the local governments. He insisted that the Austrian army, when in Hungary, would come under Hungarian law, and this was conceded by the Austrian Empire. He tried to repatriate conscript soldiers from Hungary. He established the Organisation of Militiamen, whose job was to ensure internal security. In May he started to organise the independent Hungarian Revolutionary Army and recruited men into it. Batthyány took control of the Organisation of Militiamen until Lázár Mészáros returned. At the same time he was Minister of War.

Batthyány was a very capable leader, but he was stuck in the middle of a clash between the Austrian monarchy and the Hungarian separatists. He was devoted to the constitutional monarchy and aimed to keep the constitution, but the Emperor was dissatisfied with his work. On 29 August, with the assent of parliament, he went with Ferenc Deák to the Emperor to ask him to order the Serbs to capitulate and stop Jelačić, who was going to attack Hungary. At the same time Batthyány offered Jelačić that Croatia could separate peacefully from Hungary. Batthyány's efforts were unsuccessful — even though the Emperor formally relieved Jelačić of his duties, in practice Jelačić and his army invaded Hungary on 11 September 1848.

So Batthyány and his government resigned, except for Kossuth, Szemere and Mészáros. Later, on Palatine Stephen's request, Batthyány became Prime Minister again. On 13 September Batthyány announced a rebellion and requested that the Palatine lead them. However the Palatine, under the Emperor's orders, resigned and left Hungary.

The Emperor didn't recognise the new government on 25 September. He also invalidated Batthyány's leadership and nominated Count Franz Philipp von Lamberg as the leader of the Hungarian army. But the rebels killed him on 28 September 1848 in Pest. Meanwhile, Batthyány travelled again to Vienna to seek a compromise with the Emperor. Batthyány was successful in his hurried effort to arrange the Hungarian Revolutionary Army: the new army defeated the Croatians on 29 September at the Battle of Pákozd. Batthyány realised that he could not compromise with the Emperor, so on 2 October he resigned again and nominated Miklós Vay as his successor. At the same time Batthyány resigned his seat in parliament.

As an ordinary soldier, Batthyány joined József Vidos' army, and fought against general Kuzman Todorović, but on 11 October 1848 he fell off his horse and broke his arm.

After Batthyány recovered he was again elected as a politician. Batthyány didn't want the Parliament to move to Debrecen. Because of his proposal the Parliament sent a delegation (including Batthyány himself) to General Alfred I, Prince of Windisch - Grätz to meet with him as the Parliament wanted to know Windisch - Grätz's purpose. But the general didn't want to meet with Batthyány, only with the other members of the delegation.

On 8 January 1849 Batthyány went back to Pest, where he was captured at the Károly Palace and imprisoned in the Budai barracks. When the Hungarian army was nearer Pest, Batthyány was taken away to Pozsony, Ljubljana and Olmütz (now Olomouc, Czech Republic). The Hungarians tried to rescue him many times, but Batthyány asked them not to. Batthyány insisted that his actions were legitimate and that the court had no jurisdiction.

On 16 August 1849 in Olmütz the Military Court sent Batthyány to his fate. At first they wanted to confiscate his possessions and give him a prison sentence, but under pressure from Prince Felix of Schwarzenberg and the Austrian Empire they instead sentenced Batthyány to death. The Hungarians carried Batthyány to Pest, because they hoped that Haynau (in the name of the Emperor) would give him mercy, but Haynau sentenced him to hang. In her last visit, Batthyány's wife smuggled a small sword into the prison. Batthyány tried to commit suicide by cutting his jugular veins, but he failed in the attempt. Because of the scars on his neck, the court changed the sentence to execution by firing squad. On the evening of 6 October Batthyány was drugged and because of this he walked to the New Building. He had lost much blood because of his suicide attempt so that two people had to escort him. He was relieved to see that there were no gallows. Johan Kempen, the commander of the military district in Pest and Buda knew that it was impossible to execute Batthyány by firing squad in his drugged state, but he sought no delay, so decided to shoot him in the head. Batthyány knelt in front of the firing squad and shouted: „Éljen a haza! Rajta, vadászok” ("Rejoice, my homeland, come on you huntsmen!").

Batthyány's funeral was in the city centre, in the vault of the Greyfriars Church. After the Austro - Hungarian Compromise of 1867, in 1870 his remains were moved to the newly built mausoleum in the Kerepesi Cemetery.

Batthyány's parliamentary speeches are preserved in contemporary diaries and political newspapers. His essay on growing sugar beet was printed in the periodical Magyar Gazda in 1842.