KJ Costello - Stanford

While at Santa Margarita KJ received Varsity letters in football (4) and basketball (1). He set numerous school records for passing and broke many of Carson Palmer's records. He was a Five-star recruit by PrepStar, Four-star recruit by Scout, Rivals, 247Sports and ESPN. He ranked as the nation's 13th-best recruit by PrepStar, 19th by ESPN. He was also the nation's second-best pro-style quarterback by Rivals, second-best pocket passer by ESPN, California's second-best recruit by ESPN, third by PrepStar

KJ received a scholarship to Stanford. He then transfered to Mississippi State. He was signed by the Chargers on August 1st, 2021.

High School Achievements

  • U.S. Army All-American
  • Elite 11 finalist
  • 2015 Trinity League MVP
  • 2015 all-state
  • 2016 all-state
  • Holds 19 school records
  • 8,222 career passing yards (broke Carson Palmer's school record)
  • 62 passing touchdowns (school record)
  • 19 rushing touchdowns
  • 452 single-game passing yards (school record)
  • Presidential Honor Roll (4.0 GPA or higher)

Costello redshirted his first year at Stanford in 2016. Entered 2017 as a backup to Keller Chryst, but made his first career start against UCLA after Chryst was injured. Costello returned as the backup after the game. However, he took over as the starter prior to the eighth game of the season. He remained the starter throughout the rest of the season and finished with 1,573 passing yards, 14 touchdowns and four interceptions. On December 18, 2019, Costello entered the transfer portal. On February 3, 2020, Costello announced he would be transferring to Mississippi State.

Graduate transfer from Stanford to Mississippi State. Started 25 games at quarterback for the Cardinal. Made a total of 30 career starts at quarterback. Owns his degree in political science from Stanford. Owns ten 300-yard passing games in his career (7 in 2018, 1 in 2019 and 2 in 2020). Has thrown four-or-more touchdown passes on six occasions (1 in 2017, 4 in 2018 and 1 in 2020). Responsible for 58 career touchdowns (55 pass and 3 rush). Left Stanford among the top 10 all-time in passing efficiency (No. 3; 143.8), completions percentage (No. 5; .626), touchdown passes (No. 6; 49), passing completions (No. 8; 495), total offense (No. 8 tied; 6,247 yards), passing yards (No. 9; 6,151) and passing attempts (No. 10; 791).

In 2020 was tabbed Southeastern Conference “Offensive Player of the Week” along with Maxwell and Walter Camp FBS “National Offensive Player of the Week” after throwing for a school-record 623 yards and five touchdowns at LSU on September 26. This is also the SEC record for passing yards in a single game. Also garnered Davey O’Brien and Manning Award “National Quarterback of the Week,” along with receiving a helmet sticker from ESPN’s College Football Final. Preseason candidate for the Maxwell Award, which is presented annually to the most outstanding player in college football. Named to the Johnny Unitas Golden Arm Award preseason watch list.

On May 5, 2021, it was announced that the Los Angeles Chargers were bringing in another arm for training camp this year. They extended and invitation to former Stanford and Mississippi State quarterback K.J. Costello. He met with the Bolts on at least one previous occasion during the pre-draft process. It was reported that Costello also met with the New Orleans Saints, New England Patriots and Philadelphia Eagles.


  • 2017: All-Pac-12 All-Academic Honorable Mention selection
  • 2018: All-Pac-12 Second-Team Offense selection
  • 2018: All-Pac-12 All-Academic Honorable Mention selection
  • 2018-19: Stanford Team Captain
  • 2020: William V. Campbell Trophy Semifinalist (Nation’s top football scholar-athlete)
  • 2021: Hula Bowl All-Star Game selection




  • Most Single-Game Passing Yards: 381 (15th) vs. Utah 2018
  • Most Single-Game Passing Yards: 347 (31st) at Washington State 2018
  • Most Single-Game Passing Yards: 344 (34th) at UCLA 2018
  • Most Single-Game Passing Yards: 342 (35th) vs. Oregon State 2018
  • Most Single-Game Passing Completions: 34 (5th) vs. Washington State 2018
  • Most Single-Game Touchdown Passes: 5 (Tied-2nd) at UCLA 2018
  • Most Single-Game Touchdown Passes: 4 (Tied-3rd) vs. Notre Dame 2017, vs. San Diego State 2018, vs. Washington State 2018 and vs. Oregon State 2018
  • Most Single-Game Total Offense: 387 (13th) vs. Oregon State 2018


  • Most Single-Season Passing Yards: 3,540 (2nd)
  • Most Single-Season Passing Attempts: 413 (4th) 2018
  • Most Single-Season Passing Completions: 269 (4th) 2018
  • Highest Single-Season Passing Efficiency: 155.0 (5th) 2018
  • Most Single-Season Touchdown Passes: 29 (3rd) 2018
  • Most Single-Season 300-Yard Passing Games: 7 (Tied-2nd) 2018
  • Most Single-Season Total Offense - Yards: 3,520 (3rd) 2018
  • Team Passing Leader: 2017
  • Team Passing Leader: 2018
  • Team Total Offense Leader: 2018


  • Most Career Passing Yards: 6,151 (9th)
  • Most Career Passing Attempts: 791 (10th)
  • Most Career Passing Completions: 495 (8th)
  • Highest Career Completion Percentage: .626 (5th)
  • Highest Career Passing Efficiency: 143.8 (3rd)
  • Most Career Touchdown Passes: 49 (6th)
  • Most Career 300-Yard Passing Games: 8 (4th)
  • Most Career Total Offense - Yards: 5,997 (9th)