Gentry played college basketball at Appalachian State University, where he was a point guard under Press Maravich and Bobby Cremins. In 1978 he spent one year as a graduate assistant at the University of Colorado. After one year working in private business, he returned to the bench when he received his first full-time collegiate assistant coaching job at Baylor University under Jim Haller in 1980. After one year at Baylor, Gentry returned to the University of Colorado as an assistant coach from 1981-1986 under Tom Apke. From 1986-1989, Gentry served as an assistant at the University of Kansas under Larry Brown, where they won the 1988 NCAA National Championship.