He succeeded K. T. Paul as general secretary of Young Men's Christian Association and eventually became president of the Indian YMCA. He worked as national secretary of the YMCAs of India, Burma, and Ceylon from 1919 to 1927. He along with K.T. Paul and V.S. Azariah were the prominent YMCA leaders, though, YMCA didn't directly involve in politics as it was run by the financial support of foreign donors beside an evangelistic agency, formed under the initiatives of missionaries; however, under the leadership of K.T. Paul and S.K. Datta, they made the YMCA known and respected not only in India but also in Europe and North America. He served as president of the All India Conference of Indian Christians in 1925, 1933, and 1934. After a lengthy service with YMCA, S.K. Datta was also associated with WSCF along with his wife Rena Datta. In June 1918, he was appointed a Member of the Order of the British Empire for services in the YMCA during the First World War.
National delegate
He served as a nominated member of Central Legislative Assembly to represent Indian Christian community, before Indian independence and Indian partition, from 1924 to 1926, and gave an address at the International Missionary Council meeting held at Lake Mohonk in 1921 and Jerusalem in 1928. As an Indian Christian delegate, he attended Second Round Table Conference held in London between September to December 1931—K.T. Paul and S.K. Dutta, though not followers of Gandhi and represented Indian christian community, they indeed made efforts to bring reconciliation among the opposing leaders who took part in the conference, including Gandhi, Sarojini Naidu, Madan Mohan Malaviya, Muhammad Iqbal, Ghanshyam Das Birla, Mirza Ismail, and more. As an editor of YMCA's periodical The Young Men of India, he edited many articles like India and racial relationships and promoted national consciousness among the Indian Christians during the national movement. By 1930, prominent Indian christian leaders like V.S. Azaraih, K.T. Paul, V. Chakkarai, and S.K. Dutta have come to conclusions that Indian christians would best integrate themselves into national life if they didn't cast themselves as a separate political entity. They also realized that a separate Christian electorate would further alienate them from national culture and amount to a form of compulsory segregation. In 1930, All Indian Christian Council proclaimed that "the place of a minority in a nation is its value to the whole nation and not merely to itself." In Second Round Table conference, both K.T. Paul and S.K. Datta representing Protestants took a determined stand against turning Indian Christians into a Communal political entity by Britain—imposing on them Communal representation, Communal electorate, and other Communal safeguards. A biography of S.K. Datta with name S.K. Datta and his people was published by Margarita Barns.
President of the All India Conference of Indian Christians
S.K. Datta served as the president of the All India Conference of Indian Christians, which stood for the interests of the Christian community of colonial India. He represented Indian Christians in the Second Round Table Conference, agreeing with Mahatma Gandhi in his views on minorities and Depressed Classes.
He was a devout Christian and critic of Hinduism, who believed that the Indian religions do indeed search for the truth, yet argued that they didn't provide moral and spiritual support for reform and renewal. He denounced Hinduism philosophy and its doctrines, especially Karma and Transmigration in weakening the demand for moral responsibility and social reform; according to him, only the basic teachings of Christianity could give hope to the people of India—the righteousness of God, the moral order of the created universe, the redeeming love of God manifest in Jesus Christ. He further emphasized a two-fold contribution of Christianity to India through the work of educational institutions, and through the visible Indian church, which he believed to be influential far beyond its minority status.
Critic of Western Christianity
He was cynical about Indian church for lack of spiritual depth, absence of a distinctive Indian Christian theology, and dependence on foreign leadership and money. He was even critical about the caste system operating within the Indian churches.
