He is most remembered for catching the winning touchdown pass in the Sugar Bowl on January 1, 1959, to give LSU the national championship for the 1958 college football season.

His father, Francis Ray "Fanny" Mangham (1911–1981),[3] had played basketball and football for Louisiana Tech University in Ruston.

He scored LSU's only touchdown on a nine-yard pass from College Football Hall of Famer Billy Cannon in its 7-0 win over Clemson in the 1959 Sugar Bowl.

[5] As a junior, Mangham was a starter for the 1959 LSU Tigers football team that compiled a 9–2 record, finished the season ranked third in the AP and Coaches' poll, and lost to Ole Miss, 21-0, in the 1960 Sugar Bowl.

At the conclusion of the 1959 season, Mangham was selected by a vote of the nation's sports writers to the 1959 first-team Academic All-America team.

Mangham was injured early in the game, and Pittsburgh end Mike Ditka was required to play in his place.