Education
Mangum attended Eagle High School in Eagle, Idaho. As senior he completed a school record 268 of 393 passes for 3,885 yards and 35 touchdowns.
Mangum attended Eagle High School in Eagle, Idaho. As senior he completed a school record 268 of 393 passes for 3,885 yards and 35 touchdowns.
He was named a special recognition Most Valuable Player of the Under Armour All-America Game for unselfishingly switching to the losing black team when they were down to a single quarterback. He was the Company-Most Valuable Player of Elite 11 Camp. Mangum was rated by Rivals.com as a four-star recruit and was ranked as the third best pro-style quarterback in his class.
He committed to Brigham Young University (Brigham Young University) to play college football.
He returned from his mission prior to the 2015 season. Mangum entered his first season as the backup to Taysom Hill.
After it was announced that Hill would miss the season, Mangum was named the starter. In his first career start he passed for 309 yards with two touchdowns and two interceptions and helped lead Brigham Young University to victory by completing a 35-yard touchdown pass on fourth-and-seven with 45 seconds left in the game to give Brigham Young University the lead.