He played college football for the Texas A&M Aggies and was selected by the Detroit Lions in the seventh round of the 1976 NFL draft.
His career ended after his third NFL season when he suffered severe injuries in an automobile accident.
[2] Early in the 1974 season, Associated Press sportswriter Herschel Nissenson wrote, "Remember the name Garth TenNapel.
"[3] TenNapel had recorded 20 tackles for Texas A&M in a game against Clemson University and again in an upset win over LSU the next week.
[8] On April 4, 1979, TenNapel and Falcons teammate Andy Spiva were involved in a car accident.