Drevno, who was the Trojans' running game coordinator and offensive line coach in 2014, replaces Deland McCullough, who left the Trojans in January to coach running backs for the Kansas City Chiefs.
"We are very excited to welcome back Tim to the Trojan Family," Helton said in a statement. "Through his experiences with elite college program and in the NFL, he has gained a reputation as a great teacher and he has grown his expertise in both the run game and pass protection. Adding Tim to our coaching staff will help continue the success we have had offensively and will help us reach our goal of winning a national championship."
Drevno has spent the past three years as Michigan's offensive coordinator and offensive line coach. The Wolverines rushed for more than 2,000 yards in each of those three seasons. In 2017, three Wolverines players rushed for at least 500 yards, which was a first for the program since 1991. In 2016, Michigan ranked first in the Big Ten and 11th nationally in scoring offense (40.3 points per game) and scored at least 40 points in seven games.
While the Wolverines ranked fourth in the Big Ten in rushing last year with 177.7 yards per game, Michigan was in the bottom half of the conference in scoring, passing and total offense.
Drevno and Michigan mutually decided to part ways in February.
In Drevno's first stint with the Trojans, USC finished the 2014 season with more than 2,000 total rushing yards, as Javorius Allen led the team and ranked third in the Pac-12 with 1,489 yards.