Trimble was not out of work long, accepting the head coaching position of the CFL's Hamilton Tiger-Cats on December 29, signing a one-year deal. After that first season, Trimble was a candidate for the head coaching job at his alma mater, Indiana, but remained north of the border. That decision would prove to be a wise one as the Tiger-Cats battled their way to a Grey Cup title in 1957. They capped the season with a 32-7 win over the Winnipeg Blue Bombers, who were led by Trimble's former Eagle's player, Bud Grant.