Eddy was one of the first of sixteen thousand student volunteers who emerged from the leading universities of the U.S. and Europe to serve as Christian missionaries across the world. In 1896, he went to India and worked at the YMCA-organized Indian Student Volunteer Movement. He served as its secretary for the next 15 years. Working among the poor and outcasts of India he mastered the Tamil language and served as a traveling evangelist among the students and masses of southern India beginning in Palamcottah. In 1911, he was appointed secretary for Asia by the International Committee and he divided his time between evangelistic campaigns in Asia and fund-raising in North America. He is also known today for his works with the Oxford Group evangelical group, a predecessor to Alcoholics Anonymous.