Jarrett attended the University of Southern California, where he played for coach Pete Carroll's USC Trojans football team from 2004 to 2006.

[2] As a freshman, he helped Trojan fans get over the loss of former USC standout wide receiver Mike Williams.

On fourth-and-nine with less than a minute left, Leinart threw a pass down the sideline to him and Jarrett caught it, running for 61 yards to set up the winning touchdown, the famed and controversial "Bush Push" quarterback sneak.

[citation needed] In USC's Rose Bowl loss to the Texas Longhorns he had 10 catches for 121 yards and a touchdown.

[citation needed] His height, hands, and quickness made him one of the premier receivers going into the 2006 college football season.

However, because of his lack of playing time, he was left off the 2006 list of Biletnikoff Award finalists, an omission noted by some sports writers.

[4] On January 1, 2007, he was named offensive most valuable player of the Rose Bowl Game with a career-high 203 receiving yards and two touchdowns in the 32–18 win over Michigan.

[2] At a press conference, the tearful Jarrett noted the best part of his USC career was being with his "teammates" but that he was "definitely doing it for my family, because I wasn't the most fortunate kid growing up.

[8] Originally projected as a first-round pick, Jarrett's stock fell due to his unremarkable time in the 40-yard dash.

[9] Johnson had initially stated that he would be best served by staying at USC an extra year and entering the draft as a senior.

[9] After being inactive for 7 of the first 8 games, Jarrett was activated for week 9 against the Atlanta Falcons due to the injury of 2nd string receiver Keary Colbert.

On November 1, 2009, Jarrett made his second career start in place of an injured Muhsin Muhammad, in a victory over the Arizona Cardinals.

"[14] During his sophomore year, Jarrett shared a Los Angeles apartment with quarterback Matt Leinart.