Monachino had previously worked as Pagano's defensive coordinator with the Colts from 2016-'17. The two also worked together with the Ravens in 2010-'11. Monachino replaces Brandon Staley, who wasn't retained by Pagano and moved on to the Broncos as their outside linebackers coach.
Monachino had been hired in December as the defensive coordinator at Kansas State before deciding to join the Bears.
The Bears also recently hired Deshea Townsend as their defensive backs coach. The team still has an opening for inside linebackers coach.