Prior to becoming president of CIU, McQuilkin served as headmaster of Ben Lippen School, then for 12 years as a missionary in Japan. Today McQuilkin is a speaker and writer, engaging in an extensive conference ministry across America and overseas. He also serves as president emeritus of CIU.
His writing has appeared in numerous journals and periodicals. Among the books he has authored are Understanding and Applying the Bible, Five Smooth Stones, Life in the Spirit, A Promise Kept, An Introduction to Biblical Ethics, and The Great Omission.
In 2003 McQuilkin married Deborah Jones Sink, a professor at the University of South Carolina School of Nursing. Deborah also has a teaching ministry in conferences and women's groups. Between them, Robertson and Deborah have nine children: four in Christian ministry, five in business.