In 2023, Harrell appeared in five games and made his first collegiate start against West Virginia in the Duke's Mayo Bowl, where the Tar Heels lost 30-10.

[4][5][6] With Drake Maye leaving for the NFL, Harrell competed with Max Johnson for the starting quarterback job throughout spring practices and fall training camp.

[9] The following week, Harrell made the second start of his career against Charlotte, completing 16 of 25 passes for 219 yards, two touchdowns, and an interception en route to a 38-20 victory.

[10] Harrell made another start the following week against NCCU, but only completed two of the six passes he threw for 22 yards while splitting time with Jacolby Criswell in the game.

[12] He did not play in Carolina's loss to rivals Duke the following week, as Criswell solidified his position as Tar Heel quarterback.