Though Ferrell was an all-state football star at Benedictine College Prep in Virginia, an all-male military school, he suffered through some difficult times. His father passed away when he was a freshman, and he missed his senior football season with a torn ACL. Ferrell was still ranked among the top 10 defensive end recruits in the country. Unfortunately, his bad luck continued once he arrived at Clemson, as a hand injury forced him to redshirt the 2015 season. Ferrell stood out as a freshman the following fall, sharing the team's defensive rookie of the year award with Dexter Lawrence after posting 50 tackles, 12.5 for loss, and six sacks in 15 starts. He made an impact in the ACC Championship Game (sack) and national semifinal (Fiesta Bowl Defensive MVP with three tackles for loss, sack) for the eventual title-winners. His sophomore season was even more impressive. Ferrell was named first-team All-American by the Associated Press, first-team All-ACC by league coaches and a finalist for the Ted Hendricks Award as the nation's top defensive end (63 tackles, 18 for loss, 9.5 sacks, two forced fumbles in 14 starts). Clemson coaches named him co-defensive player of the game (two tackles, sack) in the team's loss to Alabama in the national title game. The Tigers took care of business in 2018, beating Alabama thanks in part to Ferrell's All-American play. The first-team All-ACC selection and winner of the Ted Hendricks Award racked up 53 stops, 19.5 for loss, 11.5 sacks, four pass breakups, and three forced fumbles in 15 starts.