Detmer broke numerous National Collegiate Athletic Association (NCAA) records with BYU and was twice recognized as a consensus All-American.

As a senior, Detmer won high school All-American honors in football and was the Texas Player of the Year.

Detmer started only one game that year, but he made the most of the opportunity, passing for 333 yards and five touchdowns in a 65–0 victory over New Mexico.

Later, he was named Most Valuable Player of the 1988 Freedom Bowl, after entering the game as a substitute and leading BYU to a come-from-behind 20–17 victory over the Colorado Buffaloes.

[citation needed] He passed for 5,188 yards and 41 touchdowns in 12 regular-season games and finished the year with 42 NCAA records (and tied for five others).

The high point of the season was BYU's 28–21 upset victory over the top-ranked Miami Hurricanes; Detmer led the Cougars by passing for 406 yards and three touchdowns against the defending national champions.

In his final game as a Cougar, Detmer passed for 350 yards to lead BYU to a 13–13 tie against heavily favored #7 Iowa in the 1991 Holiday Bowl.

[6] Detmer spent four seasons with the Packers, but appeared in only seven games while serving as back-up to starter Brett Favre.

After Rodney Peete suffered a season ending knee injury, Detmer became the team's starting quarterback.

In his first start against the division rival New York Giants, Detmer completed 18 of 33 passes for 170 yards and no interceptions in the 19–10 victory.

A few weeks later, Detmer and the Eagles ended a three-game losing streak as they shut out the Giants in the rematch 24–0.

For the year, Detmer passed for 2,911 yards and 15 touchdowns; his 80.8 passer rating ranked fourth among NFC quarterbacks.

Detmer started the first game of the 1999 season, then served as backup until Couch sprained his foot in week 15.

His first start was a disaster: he threw seven interceptions against the Browns, the second-highest single-game total in NFL history (tied with seven other players).

Detmer spent the 2004 and 2005 seasons with the Atlanta Falcons, but did not see any action as the third-string quarterback behind Michael Vick and Matt Schaub.

Detmer is currently the head football coach at American Leadership Academy's Queen Creek campus.

[12] Detmer's brother Koy is a former NFL quarterback, and their father Sonny was a prominent San Antonio high school coach.