Bill Cowher spent many years with the Cleveland Browns, both as a player and then later as a coach, before he ended up being hired by the Pittsburgh Steelers to serve as their head coach, a role that he occupied for a decade and a half from 1992 through the 2006 season, after which he chose to resign.
A number of teams since then had inquired about his coaching services, hoping that they could reel him out of retirement, which does occasionally work (see Jon Gruden), but Cowher never budged, appreciating life with his family and in his post-coaching career as a broadcaster.