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 can compete in the marketplace of ideas when it's properly understood and properly articulated.

Greg's teaching has been featured on Focus on the Family radio, he’s been interviewed for CBN and the BBC, he’s debated atheist Michael Shermer on Hugh Hewitt’s national radio show, and did a one-hour national television debate with Deepak Chopra on Lee Strobel's “Faith Under Fire.” Greg has been quoted in U.S. News & World Report and the L.A. Times. An award-winning writer, Greg is author of Tactics—A Game Plan for Discussing Your Christian Convictions, Relativism: Feet Firmly Planted in Mid-Air with Francis J. Beckwith, and Precious Unborn Human Persons. Greg has published more than 180 articles and has spoken on nearly 60 university and college campuses both in the U.S. and abroad.

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 from Simon Greenleaf University. He is an adjunct professor in Christian apologetics at Biola University. He’s hosted his own radio talk show for over 20 years advocating clear-thinking Christianity and defending the Christian worldview.