Rajendra Prasad served in several educational institutions as a teacher. After completing his M.A. in economics, he became a professor of English at Langat Singh College in Muzaffarpur, Bihar. However, he later left college to pursue legal studies and entered Ripon College, Calcutta (now Surendranath Law College). He joined the High Court of Bihar and Odisha in 1916. He was appointed as one of the first members of the Senate and Syndicate of Patna University in 917. He practiced law in Bhagalpur, the famous silk city of Bihar. Prasad played a key role in the freedom movement. Prasad's first association with the Indian National Congress was during the annual session held in Calcutta in 1906, where he participated as a volunteer while studying in Calcutta.
Formally, he joined the Indian National Congress in the year 1911, and at that time the annual session was again held in Calcutta. During the Lucknow session of the Indian National Congress held in 1916, he met Mahatma Gandhi. He responded to Gandhi's call for a boycott from Western educational institutions to ask his son Mrityunjaya Prasad to quit his studies and enroll himself in Bihar Vidyapeeth. He also played an active role in helping the people affected by the 1914 floods in Bihar and Bengal. When there was an earthquake in Bihar on 15 January 1934, Prasad was in jail at that time. During that period, he visited his close aide Anugrah Narayan Sinha for relief work. He was released two days later and on 17 January 1934 formed the Bihar Central Relief Committee and raised funds to help the affected people. After the Quetta earthquake on 31 May 1935, when he was refused to leave the country due to government orders, he established the Quetta Central Relief Committee in Sindh and Punjab under his chairmanship.
He was elected as the President of the Indian National Congress during the Bombay session in October 1934. In 1939, when Subhash Chandra Bose resigned as the President of the Indian National Congress. He was then elected president again. On 8 August 1942, the Congress passed the Quit India Resolution in Bombay that led to the arrest of several Indian leaders. Prasad was arrested at Sadaqat Ashram in Patna and sent to Bankipur Central Jail. He was released on 15 June 1945 after living for almost three years. After the formation of an interim government of 12 nominated ministers led by Jawaharlal Nehru on 2 September 1946, he was allotted the Food and Agriculture Department. On 11 December 1946, he was elected as the President of the Constituent Assembly. On 17 November 1947 he J.J. B. He became the Congress President for the third time after Kripalani submitted his resignation. Two and a half years after independence, on 26 January 1950, the Constitution of Independent India was ratified and Prasad was elected the first President of the country. Unfortunately, the night of 25 January 1950, one day before the Republic Day of India, his sister Bhagwati Devi passed away.