Glenn served as backfield coach at the University of South Dakota in 1974. He was also a backfield coach at Northern Arizona University in 1975. Glenn's first head coaching job was at Doane College in Crete, Nebraska. There he was the youngest head college football coach at 27 years of age. While at Doane he compiled a 21–18–1 record over four seasons. After Doane, Glenn made his first stint at the University of Montana as a quarterbacks and wide receivers coach and offensive coordinator from 1980 to 1985. He was out of coaching in 1986. In 1987, he joined the staff at University of Northern Colorado (UNC) as quarterbacks and kicking coach. He was named head coach of UNC for the 1989 season.