Karsen Barnhart (born March 2, 2001) is an American football offensive tackle for the Los Angeles Chargers of the National Football League (NFL). He played college football for the Michigan Wolverines, where he was an All-Big Ten selection, winning three consecutive Big Ten Conference titles and a national championship in 2023.

Barnhart was born in Paw Paw, Michigan where he attended Paw Paw High School, playing baseball, basketball and football.^[1] He played his junior season at Paw Paw at tight end, after spending his first two years on the offensive line.^[2] He was ranked a four-star recruit, and the No. 15 guard and No. 7 player in Michigan by 247Sports.^[3] He received offers from Michigan, Michigan State, Indiana, Iowa, Nebraska, Minnesota and USC.^[4][5]

Barnhart committed to the University of Michigan in April 2018.^[6][7] As a freshman in 2019, he appeared in two games at left tackle, and played special teams in one game. He made his collegiate debut on August 31, 2019, in a game against Middle Tennessee.

As a sophomore in 2020, he appeared in all six games, with four starts at left tackle. He started in place of the injured Ryan Hayes, in a season that was shortened due to the COVID-19 pandemic.^[8]

As a junior in 2021, he appeared in 10 games, including two starts at left guard. He was a part of the Joe Moore Award winning offensive line.^[9][3]

As a senior in 2022, he started appeared in ten games, with nine starts, at tackle and was again part of the Joe Moore Award-winning offensive line.^[10] Following the season he was named All-Big Ten honorable mention.^[11] He was also named Michigan's most improved player on offense.^[12]

As a graduate student in 2023, he started all 15 games for Michigan’s national championship team, including starts at right tackle, right guard and left tackle.^[13] After offensive guard Zak Zinter sustained a broken tibia and fibula in Michigan's final regular season victory against Ohio State, it was announced Barnhart would shift from right tackle to guard for the remainder to the season.^[14] Following the season he was named second-team All-Big Ten by the coaches.^[15][16]

On January 6, 2024, Barnhart declared for the 2024 NFL draft.^[17]

On April 27, 2024, Barnhart signed with the Los Angeles Chargers as an undrafted free agent, reuniting him with former Michigan head coach Jim Harbaugh.^[20][21][22]