"We are excited to add a talented and accomplished coordinator in Jim Schwartz to our staff," Bills coach Doug Marrone said in a statement. "Schwartz has led aggressive and productive defensive units throughout his time in the NFL and we feel our defense will continue to improve."
Schwartz, 47, was a defensive coordinator for the Tennessee Titans before getting hired by the Lions. He had a 29-52 record, including one playoff loss, in five years as Detroit’s coach.
He lost his job after the Lions dropped six of their final seven games to finish with a 7-9 record, two years after Schwartz had taken them to the postseason.
The Bills also hired former Lions quarterback coach Todd Downing, 33, as their QB coach.