Nate Hybl beat out White for the starting quarterback job in 2001. Hybl hurt his right side in the first quarter of the Sooners' 14-3 win over #5 Texas and did not return. White replaced him and was 16-of-23 for 108 yards and ran 12 times for a team-high 38 yards. He started the next week against Kansas, throwing four touchdown passes to tight end Trent Smith. White continued to start the following games for the Sooners including a showdown with Nebraska, featuring the top two teams in the BCS for the second consecutive year. During the second quarter, White injured his ACL while completing a long pass to running back Quentin Griffin, ending his season.
The 2002 season started out with a preseason battle for the starting quarterback position between White and Hybl. White eventually won a close battle and was named the starter for the first game against Tulsa. After a slow start, the offense finally got rolling and they easily cruised to a shutout win. In the second game, the Alabama Crimson Tide came to Norman. White again went down with a knee injury, this time tearing the ACL in the opposite knee. Hybl came in as a backup and led the team to a hard-fought come-from-behind win, but the offense experienced some struggles in the second half. White would again be out for the season and Hybl led the team to a Big 12 championship and a victory over Washington State in the 2003 Rose Bowl game, being named MVP.
After suffering from consecutive anterior cruciate ligament tears, White had reconstructive knee surgeries on both knees during the 2001 and 2002 seasons. Despite the fact that White could not scramble and the Sooners had to run every offensive play out of a shotgun formation, White won the Heisman Trophy in 2003 after throwing 40 touchdown passes and 8 interceptions. White was also the recipient of the Associated Press Player of the Year, unanimous All-American, consensus Big 12 Offensive Player of the Year, the Davey O'Brien Award, and the Jim Thorpe Courage Award in his 2003 season. He was also the 2003 NCAA QB of the Year as awarded by the Touchdown Club of Columbus. He was awarded a medical hardship by the NCAA and allowed to play a second senior year in 2004. He led the Sooners to the Big 12 championship game in 2003, which they lost to Kansas State.
White was granted a medical hardship for the 2004 season. He was again a finalist for the Heisman Trophy in 2004, trying to become just the second player after Archie Griffin to win the honor twice, but instead finished third behind his Sooner backfield mate, runner-up Adrian Peterson, and winner Matt Leinart. White did win the Davey O'Brien Award for the second straight year, becoming the third quarterback ever to win the prestigious award two years in a row. White and Peterson led the Sooners to another national championship game, the Orange Bowl, in 2004, but lost 55–19 to Leinart's USC Trojans. White finished his collegiate career as the University of Oklahoma's all-time leader in career passing yards (8,012) and touchdown passes (81).
White's on-the-field accomplishments have been further honored in Tuttle with the painting of a local water tower to read "Home of Jason White 2003 Heisman Trophy Winner". This tower is readily seen from the center of town, just west of State Highways 4 and 37. Additionally, a section of Cimarron Road in the city was renamed "Jason White Boulevard".
Despite his strong college career, White was not selected in the 2005 NFL Draft and did not receive a tryout from any NFL team in the first several weeks of post-draft free agency. White became the only Heisman Trophy winner to be unsuccessful in an attempt to play professional football and just the third Heisman Trophy winner not to be drafted in the NFL after Pete Dawkins instead chose a military career and Charlie Ward chose a career in the NBA. He did eventually receive a tryout from the Kansas City Chiefs, who opted not to sign him. Eventually, the Tennessee Titans signed him as an undrafted free agent in 2005 for two years, but White decided not to attempt to play, citing weak knees. White has expressed an interest in coaching.
Today, White owns and operates the Jason White Companies, which owns A Store Divided, an OU/OSU memorabilia store, and a The Athlete's Foot shoe store. He also worked with insurance agent Steve Owens, another former Sooner Heisman Trophy winner and former athletic director at the University of Oklahoma. Prior to that, White worked briefly for a securities firm in downtown Oklahoma City. He is a co-founder and board member of St. Anthony Hospital's YourCARE Clinic community health centers.
In 2007, a bronze statue of White was dedicated on the University of Oklahoma campus in Heisman Park, commemorating his 2003 award.