James Bruce Dillon was born in 1943 in Bloomington, Illinois. He became a Christian at the age of nine while attending the local Evangelical United Brethren Church with his family (As an adult he was a member of first the Conservative Baptist, then the Evangelical Free churches). His family moved to Washington state while he was a boy and he grew up there. After graduating from high school in 1961 he attended the University of New Mexico for one year and then dropped out to enlist in the Navy. After his military service ended, he held various jobs until he was hired by Pacific Northwest Bell Telephone Company in Seattle, Washington as a technician. About this time he met Ruth Elaine Reese. She was the daughter of missionaries to Japan. They were married in 1967. James began attending the Multnomah School of the Bible part time in 1968. He and Ruth decided they wanted to enter full-time Christian work. They join Sudan Interior Mission in 1972. The next year James quit the phone company to attend Multnomah full-time. He graduated with a BA in religious education in 1975. The Dillons (including their two children James Jr. and Cheralee Ruth) went to Liberia in 1976, where James worked as a technician at SIM's radio station ELWA while Ruth was a secretary. Eventually James became a Bible teacher and advisor to several Liberian pastors who broadcast over ELWA. He was very influenced by a psychology seminar taught by James Plueddemann which he attended in 1980. He and Ruth both decided to get further education. They returned to the United States in 1982 and enrolled at Wheaton College, he in the graduate communication program, she in the undergraduate program. They both matriculated in December, 1983 and returned to Liberia in 1984.

James continued to work with pastors and also was placed in charge of developing an orientation program for new missionaries and a continuing education program for the rest of the staff. Ruth became the station's public information officer. Their children attended the Ivory Coast Academy, a boarding school in Bouake, Ivory Coast. In 1986 they returned to the United States on furlough. While there James was offered a position at SIM's headquarters in Charlotte, North Carolina. He worked there as a researcher, studying how new population and cultural trends would effect the preaching of the gospel.