Kiffin, 34, succeeds Pete Carroll as coach of the Trojans after completing just one season of a six-year contract with the Volunteers. Carroll left USC to become coach of the Seattle Seahawks.
USC Athletic Director Mike Garrett said he was excited to bring Kiffin back to the school where he worked for Carroll from 2001-06, rising to offensive coordinator for the 2005 and 2006 seasons while also handling recruiting.
Kiffin left USC to become head coach of the Oakland Raiders, where he compiled a 5-15 record before his departure in a bitter feud with Raiders owner Al Davis. Kiffin led Tennessee to a 7-6 record this season with an appearance in the Chick-Fil-A Bowl.
"I was able to watch him closely when he was an assistant with us and what I saw was a bright, creative young coach who I thought would make an excellent head coach here if the opportunity ever arose," Garrett said. "I'm confident he and his staff will keep USC football performing at the high level that we expect.
"Lane brings a lot to the table. He has a coaching background both in the pros and in the best collegiate conferences. He has a great command of the X's and O's. He is familiar with the Trojan landscape and will be a great representative of our university. He keeps the game fun. And, very importantly, he has proven to be one of the finest recruiters anywhere."
Kiffin will bring his father, defensive coordinator Monte Kiffin, and recruiting coordinator Ed Orgeron along with him from Tennessee.