Wilson spent the 2013 season in the same position with the Bulldogs and previously was defensive coordinator at Mississippi State. He began his coaching career in 1993 at Indiana State with additional stops at Northern Illinois, Northeastern Oklahoma A&M, Illinois State, Army, Colorado and Oklahoma.
Wilson steps in to replace Bo Davis, who accepted the same position at Alabama just one week after being introduced at USC. Davis told USC head coach Steve Sarkisian that he was leaving for family reasons.
Ed Orgeron was the defensive line coach this past season before taking over as interim head coach for the fired Lane Kiffin. He led a revival for the Trojans, who finished with a 10-4 record.
Orgeron resigned when he was not offered the permanent head-coaching job, although Sarkisian said he would pursue Orgeron to return to USC and Orgeron was reported to be a candidate for the defensive line opening.
ESPN.com's Alex Scarborough and ESPNLosAngeles.com's Arash Markazi contributed to this report.