As a true freshman at Iowa in 2019, Campbell played in 11 games and had five tackles. As a sophomore in 2020, he played in five games and had 29 tackles, one sack and one interception. He returned as a starter his junior year in 2021, recording 140 tackles, two interceptions, a sack and a touchdown. After the 2021 season, Campbell was named first-team all Big Ten, leading one of the best defenses in the country. Campbell returned to Iowa in 2022, and was named the preseason Big Ten defensive player of the year by Big Ten media. Campbell led the elite Iowa defense in 2022 to a nationwide best in yards per play average and top five in total defense and defensive efficiency. Campbell finished the regular season with 118 tackles, ranking second in the Big Ten and tied for 13th nationally, adding two interceptions, one recovered fumble and one forced fumble. Against
Minnesota, Campbell's forced fumble and long interception return, both in the fourth quarter, enabled Iowa's victory despite being outgained and having much less time of possession. Following the season, Campbell was given the 2022
Butkus Award as the top linebacker in college football as well as the
William V. Campbell Trophy as a scholar-athlete. He was also named the Big Ten's
Nagurski–Woodson Defensive Player of the Year and
Butkus–Fitzgerald Linebacker of the Year. ==Professional career==