He had previously served as a special adviser to head coach Herman Edwards but will now be a full-time member of the staff.
Antonio Pierce will work as the other co-defensive coordinator.
Lewis spent 16 years leading the Bengals' coaching staff. He compiled 131-122-3 record during the regular season and earned seven playoff appearances, but the team failed to win a game in the postseason.
The 61-year-old Pennsylvania native mutually parted ways with Cincinnati following the 2018 season and spent the 2019 campaign as a special adviser to Herm Edwards at Arizona State.
"I don't think so. I'm fine," Lewis said, adding he didn't miss the NFL.
In all, the 2009 AP Coach of the Year has nearly four decades of coaching experience dating back to serving as a linebackers coach at Idaho State, his alma mater, starting in 1981.
Lewis was selected to serve as a head coach for the 2020 NFLPA Collegiate Bowl in January and discussed his love of the college game.
"My coaching career started at the college level, so it's always held a special place in my heart," he said in a press release. "I'm looking forward to working with some of the country's best prospects at the Collegiate Bowl and helping prepare them to succeed as professionals."
Arizona State now adds another experienced coach to the staff as the squad tries to improve upon its 8-5 record from this past season, which included a win in the Sun Bowl.
The defense ranked 35th in the country at 22.4 points allowed per game.
Lewis has the potential to attract recruits thanks to his name recognition, but there's still a learning curve for someone entering that role for the first time.