William Farmer was the son of a Presbyterian minister. He was a graduate of Washington & Jefferson College in Washington, Pennsylvania, and Western Theological Seminary, and was ordained a Presbyterian minister. After a year at Rehoboth Presbyterian Church in Belle Vernon, Pennsylvania, he was called to the Edgewood Church and served there for eleven years before returning to the seminary as a professor of the New Testament. He took post gradate training in theology at the University of Marburg, Germany. As a civilian minister working with the Y.M.C.A. during World War I, he served the men of the 5th Regiment (Marines) in France. After the war he served for several years as summer pastor of the Community Church of Hyannis port, Massachusetts, and served as interim pastor of the East Liberty Presbyterian church, Shadyside Presbyterian Church, and Sixth Church, among others. He was guest professor of preaching at Princeton Theological Seminary, and received honorary degrees from Washington & Jefferson College, and served on that college’s board of trustees. He also received an honorary Doctor of Laws degree from Waynesburg, College.