The first session of the Indian National Congress was held in December 1885 in Bombay with seventy two delegates. More than just a political party, Congress was an assembly for politically-minded individuals who were interested in reform. In its first twenty years, known as a 'moderate phase', Congress was not interested in campaigning for independence or self-rule but for greater political autonomy within empire. After the 1905 Partition of Bengal, Congress became more vocal and active in demanding substantial political reform, and eventually voiced demands for full independence from Britain.

The majority of the founding members of Congress has been educated or lived in Britain, including of course Allan Octavian Hume. Badruddin Tyabji, W. C. Bonnerjee, Surendranath Banerjea, Pherozeshah Mehta, and the brothers Manomohun and Lalmohan Ghose had all studied in London, and had all fallen under the influence of Dadabhai Naoroji.

Congress had a British committee based in London, acting as a lobby group in Britain, which was founded in 1889. Dadabhai Naoroji, when he was an MP in London, attended this group's meetings, and was associated with their parliamentary pressure group. In 1890, the committee began to produce India, a free monthly journal summarising Indian news for the British press and politicians. India became a weekly subscribed journal, 1898-1921. Its editors included Henry Cotton (1906-19) and Henry Polak (1919-20). It became a welcome and useful publication for the growing number of Indian students in Britain as well.

As Congress came under the influence of M. K. Gandhi in the 1920s, further former-students from Britain became prominent within the party such as Jawaharlal Nehru and Subhas Chandra Bose. Congress was transformed from an assembly dominated by Western-educated elites to a mass organization that appealed to diverse sections of the Indian public in these decades. Representatives of Congress met with British politicans in the 1930s and 1940s to negotiate the terms of independence, often at odds with the British. They also found it hard to appease their many constituents and their rivals, the Muslim League. On 15 August 1947, with the independence of India and Pakistan, Congress became the ruling party of India with Jawaharlal Nehru the first Prime Minister.