Gary DeMar grew up in the suburbs of Pittsburgh, Pennsylvania. He is a graduate of Western Michigan University (1973) and earned his M.Div. at Reformed Theological Seminary in 1979. He has lived in the Atlanta area since 1979 with his wife Carol. They have two grown sons. Gary and Carol are members of Midway Presbyterian Church (PCA).

Gary has been interviewed by Time magazine, CNN, MSNBC, FOX, the BBC, and Sean Hannity. He has done numerous radio and television interviews, including the Bible Answer Man, hosted by Hank Hanegraaff. Newspaper interviews with Gary have also appeared in the Washington Times, Toledo (Ohio) Blade, the Sacramento Bee, the Atlanta Journal/Constitution, and the Chicago Tribune. American Vision also publishes The Biblical Worldview, a monthly magazine edited by Gary.