[10] In May 2022, Addison announced that he would be transferring to the University of Southern California to play for the USC Trojans football team.

[11] He chose to wear #3 for the Trojans, which was previously retired in honor of Carson Palmer, the 2002 Heisman Trophy winner.

[21] On July 20, 2023, Addison was pulled over and cited for speed and reckless driving before reporting to his first training camp.

[22][23] Addison told a police officer at the scene that he was driving at that speed due to a medical emergency involving his pet dog.

[26][27] Shortly before midnight on July 12, 2024, Addison was arrested near the Los Angeles International Airport (LAX) on suspicion of driving under the influence of alcohol.

[28][27][29] At the time of his arrest, California Highway Patrol (CHP) officers found Addison asleep at the wheel, with his car blocking traffic lanes.