Harrell attended Berkeley Prep and was rated a 4-star prospect after collecting 58 tackles, 11 tackles for loss and 3 sacks as a senior. Was rated the 12th best weakside defensive end in the country before he committed to Michigan.
Jaylen Harrell appeared in 4 games on special teams as a freshman and collected 4 tackles for the Wolverines. In 2021, he appeared in all 14 games, starting 3 of those at outside linebacker and also contributed on special teams. He tallied 15 tackles, 2.5 for loss and 1 quarterback hurry in his limited time.
As a junior, he was an All-Big Ten honorable mention in a season that saw him start in 12 games on the edge. His 30 tackles, 7.5 for loss, and 3.5 sacks put Harrell on the map of NFL scouts. In 2023, Harrell played in 15 games and collected 31 tackles, 9 TFL, and 6.5 sacks.