After coming into their influence, he abandoned his role as a freedom fighter and renounced the world to join the Ramakrishna Order. As a "Brahmachari", for many years he devoted himself to the study of the scriptures under eminent teachers, practised spiritual disciplines, and served the Order in various capacities, until, in 1931, he was deputed by the Order to come to America as one of its representatives. In 1933 he founded the Ramakrishna-Vivekananda Center in New York. Nikhilananda was considered a brilliant speaker and was invited to lecture at different universities, churches, and synagogues, and to participate in inter-religious conferences East and West. He served at the Ramakrishna-Vivekananda Center till his death in 1973. Nikhilananda made important contributions to the literature of Ramakrishna movement. He also attracted distinguished disciples, including author JD Salinger, Margaret Woodrow Wilson, daughter of the president Woodrow Wilson, the comparative mythologist Professor Joseph Campbell, and Chester Carlson, inventor of xerographic process. Philosopher Lex Hixon was Nikhilananda's disciple.