He played college football for the USC Trojans, where he won the Heisman Trophy and led his team to an undefeated season as a junior.

Selected tenth overall by the Arizona Cardinals in the 2006 NFL draft, Leinart primarily served as Kurt Warner's backup for four seasons.

He underwent surgery when he was three years old and was fitted with special glasses to correct the problem, but the eyewear combined with Leinart's already-overweight frame made him an easy target for other children's ridicule.

As a junior, he led his team to a California Interscholastic Federation (CIF) Division I co-championship and was named the Serra League's Offensive Most Valuable Player.

[6] As one of the nation's top college football recruits, Leinart committed to USC under coach Paul Hackett, noting that a major factor was offensive coordinator Hue Jackson.

[7] However, after Hackett and most of his staff were fired in 2000, Leinart considered other programs such as Georgia Tech and Arizona State, and visited Oklahoma and Michigan before USC eventually hired Pete Carroll.

[8][9][10] Leinart attended the University of Southern California, where he played for coach Pete Carroll's USC Trojans football team from 2001 to 2005.

As a sophomore in 2003, Leinart competed with redshirt junior Matt Cassel, who was Palmer's backup the previous season, and Purdue transfer Brandon Hance for the vacant starting quarterback position.

[14] Going into the season, Carroll and his coaching staff selected Leinart, not because he had set himself significantly ahead of the pack in practice, but because they had to pick one of the three as the starting quarterback.

Leinart injured his knee in the second quarter and was not expected to play again that day, but he returned to the game and finished 13-of-23 for 289 yards in a 37–17 victory.

[37][38] Leinart received Orange Bowl MVP honors and the Trojans claimed their first BCS National Championship and second straight No.

[46] Leinart was again invited to New York for the Heisman ceremony along with teammate Reggie Bush and Texas quarterback Vince Young.

Scouts considered Leinart to be the archetypal NFL quarterback in size at 6 ft 5 in (1.96 m) and 225 pounds (102 kg), although his arm strength drew concerns.

Cardinals head coach Dennis Green held a press conference after a poor performance by Warner in Week 3 and announced Leinart would start.

In a November 26 game against the Minnesota Vikings, Leinart set a then-NFL rookie record with 405 passing yards, but only produced a quarterback rating of 74.0 as the team ultimately lost.

After a sequence of drives, the offense stalled, which led new head coach Ken Whisenhunt to begin inserting Warner as a situational quarterback.

Finally, after Leinart threw three interceptions within a matter of minutes versus the Oakland Raiders in the third preseason game, Warner was named the opening-day starter.

The Cardinals released Leinart on September 4, two days after the final preseason game, in favor of Anderson and rookies Max Hall and John Skelton.

[72] On September 6, 2010, the NFL announced that Leinart signed a one-year contract to back up Matt Schaub with the Houston Texans.

Leinart started for the first time in Week 12 against the Jacksonville Jaguars; however, during the first half he fractured his collarbone and was replaced by rookie quarterback T. J.

[77] Leinart signed with the Oakland Raiders on May 1, 2012, as a backup to his former college teammate and fellow Heisman winner Carson Palmer.

After injuries to quarterbacks EJ Manuel (knee surgery) and Kevin Kolb (concussion), the Bills decided to sign Leinart on August 25, 2013.

[80] Leinart and Thad Lewis (who was brought in on the same day through a trade) would compete for the fourth-string quarterback job behind undrafted rookie Jeff Tuel.

[citation needed] In May 2018, Leinart married Make It or Break It and The Mentalist actress Josie Loren at the Basilica of St. Lawrence in Asheville, North Carolina.