Tanner attended Justin F. Kimball High School, where, as a junior he was named All-district after posting 1,395 rushing yards and 22 touchdowns.
As a true freshman, he played 13 games as a defensive back in nickel situations, tallying 16 tackles and one sack.
Tanner became a full-time starter as a senior, but was forced to redshirt after starting two games, because of a bone contusion he suffered in his knee during the second contest of the season.
[1] On August 21, playing against the San Diego Chargers at Cowboys Stadium, he lost his helmet while scoring a touchdown in the second half of the game.
On July 29, 2014, Tanner was signed by the Indianapolis Colts as a free agent, after releasing running back Chris Rainey.
On August 27, 2014, he was signed as a free agent by the Dallas Cowboys to play in the last game of the preseason, because of injuries at the running back position.
[9] In March 2020, he joined former Cowboys teammate Jon Kitna's coaching staff at Burleson High School.