Gentry played college football at the University of Southern California where he was also a member of Phi Kappa Tau fraternity. At USC, he played on the 1931 and 1932 Rose Bowl championship teams. He was a decorated soldier, serving as an intelligence officer in World War II and later was national commander of the Veterans of Foreign Wars. Gentry's post-football career was in the law and he was city attorney of Pasadena, California for sixteen years. He was also a published writer and poet.