After beginning his college football career with the Texas Tech Red Raiders, Mayfield played for the Oklahoma Sooners, where he won the Heisman Trophy in 2017, becoming the first walk-on player to ever win the award.

Mayfield set the NFL rookie quarterback record for passing touchdowns during his first season, along with ending a 19-game winless streak for the Browns in his debut.

Due to a performance decline and conflict with Browns management, Mayfield was traded from Cleveland in 2022, spending the year with the Carolina Panthers and Los Angeles Rams.

[2][7] James, a private equity consultant, encountered financial difficulties during his younger son's senior year in high school.

[15] The game featured the last four former Lake Travis quarterbacks combined on both teams: Garrett Gilbert, Michael Brewer, Collin Lagasse, and Mayfield.

[17] After being affected by a knee injury and losing the starting job to fellow true freshman Davis Webb, Mayfield finished the season with 2,315 yards on 218-of-340 completions with 12 touchdowns and 9 interceptions.

[18] Mayfield was named one of 10 semifinalists for the Burlsworth Trophy in November; the award is given to the best player in Division I football who began his college career as a walk-on.

[22][better source needed] After playing for Texas Tech, Mayfield transferred to the University of Oklahoma in January 2014, but had not contacted the Sooners coaching staff.

Mayfield further elaborated in an interview with ESPN that he sought to transfer due to scholarship issues and a perception that he had earned the starting position and that further competition was not "really fair".

[28][29] Mayfield finished the year with 3,700 passing yards, 36 touchdowns, and seven interceptions, a résumé which propelled him to fourth place in voting for the Heisman Trophy.

[33] On October 22, in a 66–59 victory over Texas Tech, Mayfield had 545 passing yards and seven touchdowns in a historic matchup against future NFL quarterback Patrick Mahomes.

Big 12 Conference rules additionally stipulate that intra-conference transfers will lose one year of eligibility over and beyond the one-year sit-out imposed by the NCAA.

[56][57] On June 1, 2016, the Big 12 faculty athletic representatives voted against a rule proposal that would have allowed walk-on players to transfer within the conference and not lose a year of eligibility.

[67] In Week 5, Mayfield threw for 342 passing yards and one touchdown as he earned his first victory as a Browns starter, in a 12–9 overtime win over the Baltimore Ravens.

As reported by The Plain Dealer, Mayfield "pretended to expose his private parts" to Browns offensive coordinator Freddie Kitchens after throwing a touchdown to tight end Darren Fells.

[75] On December 30, in the regular-season finale against the Ravens' league-best defense and fellow rookie quarterback Lamar Jackson, Mayfield threw for 376 yards and three touchdowns, but his three costly interceptions — one of which came at the hands of linebacker C. J. Mosley with 1:02 left in the fourth quarter while attempting to drive the team into range of a game-winning field goal attempt — ultimately contributed to a 26–24 loss.

[94] Mayfield was replaced by Case Keenum in the third quarter due to aggravation of a minor rib injury he suffered in the previous week's game.

Mayfield came close to throwing six first-half TDs, as Peoples-Jones dropped a would-be touchdown, leading to a field goal, and running back Nick Chubb wrapped up the scoring with a one-yard run near the end of the first half after Mayfield completed a 17-yard pass play to Rashard Higgins, setting up Chubb for the score.

In the Week 9 game against the Bengals, the Panthers were trailing 35–0 at halftime behind a disastrous start by Walker; Interim Head Coach Steve Wilks inserted Mayfield for the second half, in which he threw for 155 yards and two touchdowns in the 42–21 loss.

[133] With only two days for Mayfield to learn the playbook after he was claimed, the Rams started John Wolford at quarterback for their game against the Las Vegas Raiders.

[137] In a Week 16 matchup against the Broncos, Mayfield led the Rams to a dominant 51–14 win while completing 24 of 28 pass attempts for 230 yards and throwing for two touchdowns.

[140] Mayfield was brought in to compete against Kyle Trask and John Wolford to determine who would be the successor at starting quarterback to Tom Brady after he retired after the 2022 NFL season.

[154] In a rematch of last season's Divisional round playoff game, Mayfield completed 12 passes for 185 yards and ran for a go-ahead touchdown as the Buccaneers beat the Lions 20–16.

[155] After a poor performance against the Denver Broncos, Mayfield rebounded the following week against the Eagles, throwing for 347 yards and accounting for three touchdowns as Tampa improved to 3–1.

[161] Mayfield cut down on his interception miscues and led last-minute game-tying drives against the Chiefs and 49ers, but the Buccaneers lost both games, dropping to 4–6 heading to their bye week.

[162] With the return of Mike Evans following the bye, Mayfield had an efficient game against the Giants, completing 24 of 30 passes for 294 yards, no interceptions, and a rushing touchdown as the Bucs won 30–7, snapping their four-game skid.

[163] Against the Panthers in Week 13, Mayfield rallied from an Achilles injury and a poor first half to lead Tampa to a game-winning field goal drive in overtime.

[166] Needing a win against the Saints to clinch the NFC South, Mayfield led three touchdown drives in the second half and rallied his team from a double-digit deficit to secure their fourth straight division title.

The preliminary police report described Mayfield as unable to walk straight, having slurred speech and food covering the front of his shirt.

The ads showed him living "at home" in FirstEnergy Stadium with his wife and performing household chores like mowing the lawn and holding a yard sale.