Klingler was selected in the first round of the 1992 NFL draft by the Cincinnati Bengals, but his career was cut short by an elbow injury.
On November 17, 1990, Klingler threw for an all-Divisions record 11 touchdown passes for a single quarterback against Eastern Washington at the Astrodome (since equaled at the NAIA level by Lee Kirkland of Pikeville in 2024[1]), and on December 2 set the NCAA (Division I) record for most yards gained in a single game, 716[2] (since surpassed by Connor Halliday in 2014 and later Patrick Mahomes in 2016).
Klingler made a valiant push to win the Heisman Trophy (following in the footsteps of fellow Cougar Andre Ware) but was eventually beaten by Ty Detmer of BYU and Raghib Ismail (runner-up) of Notre Dame.
Klingler remained a stand-out for the University of Houston and still ranks in the FBS top ten for career touchdown passes and yards.
In 1998, he signed with the Green Bay Packers to back up Brett Favre, but he was cut and didn't play.