Later, Peters was an assistant coach for various teams. He was defensive coordinator of the Minnesota Vikings from 1986 to 1990 where his defenses ranked number 1 in the NFL in '88 and '89 (71 sacks in '89, one short of an NFL record), and of the Tampa Bay Buccaneers from 1991 to 1994. During this time his nickname was 'Sgt. Rock.' He was also well known in Tampa Bay for wearing bright orange pants to practice.
Peters has four sons (Craig, Allen, Dean and Kelly) and a wife, Nancy.