Greg started out thinking he was too smart to become a Christian and ended up giving his life for the defense of the Christian faith. A central theme of Greg's speaking and writing is that Christianity—if it's properly understood and properly communicated—makes the most sense of the world as we find it.

Greg has spoken on more than 80 college and university campuses both in the U.S. and abroad and has hosted his own call-in radio show for 30 years advocating “Christianity worth thinking about.” He’s debated atheist Michael Shermer on national radio and Deepak Chopra on national television on Lee Strobel's “Faith Under Fire.” An award-winning writer and best-selling author, Greg has written seven books, including Tactics—A Game Plan for Discussing Your Christian Convictions; The Story of Reality—How the World Began, How It Ends, and Everything Important that Happens in Between; and Relativism: Feet Firmly Planted in Mid-Air. Greg has been featured on Focus on the Family radio and has been interviewed for CBN and the BBC. He's been quoted in Christianity Today, the U.S. News & World Report, and the L.A. Times.

Greg received his Masters in Philosophy of Religion and Ethics at Talbot School of Theology, graduating with high honors, and his Masters in Christian Apologetics with honors from Simon Greenleaf University. He is an adjunct professor in Christian apologetics at Biola University.