Keene attended Chandler High School in Chandler, Arizona.[2] As a junior, Keene recorded 193 completions for 2,835 yards and 23 touchdowns.[3] In his senior season, Keene threw for 2,069 yards and 22 touchdowns on 154 completions, leading Chandler to a state championship.[4] A three-star recruit, he committed to play college football at the University of Central Florida.[5]
Keene entered the 2021 season as the backup to Dillion Gabriel. After an injury to Gabriel, Keene became the starter as a true freshman.[6][7] He made ten starts, totaling 1,730 yards and 18 total touchdowns.[8] Keene threw for 144 yards and one touchdown in the 2021 Gasparilla Bowl, leading UCF to a 29–17 over Florida.[9] Keene entered the 2022 season as the backup to John Rhys Plumlee, where he would only appear in four games. He finished the season with 647 yards and six touchdowns before entering the transfer portal.[10][11]
On December 21, 2022, Keene announced his decision to transfer to Fresno State.[12] Entering the 2023 season, he was named the starting quarterback.[13] In the season opener against Purdue, Keene threw for four touchdowns and 366 yards, leading Fresno State to a 39–35 victory.[14][15] Against Arizona State, Keene threw for 281 yards and two touchdowns, leading Fresno State to a 29–0 shutout win.[16] Keene led Fresno State to a 9–4 record and a 37–10 victory in the 2023 New Mexico Bowl. In the New Mexico Bowl, he threw for a career-high 380 yards and recorded four total touchdowns, being named the game's offensive MVP.[17][18][19] Keene finished the season throwing for 2,976 yards and 24 touchdowns.