The redshirt freshman beat out Notre Dame linebacker Manti Te'o and Kansas State quarterback Collin Klein.
A few days after turning 20, Manziel became the most inexperienced player to win the Heisman. Adrian Peterson had come closest as a freshman, finishing second to Southern California quarterback Matt Leinart in 2004.
Manziel is the second player from Texas A&M to win the Heisman, and first since John David Crow 1957.
Manziel broke 2010 Heisman winner Cam Netwon's Southeastern Conference record with 4,600 total yards this season, led the Aggies to a 10-2 in their first SEC season and orchestrated an upset at No. 1 Alabama in November that stamped him as legit.