‘Law & Order Toronto’ is switching up detectives, with Luke Kirby cast for Season 4.

A casting shake-up on “Law & Order Toronto: Criminal Intent” will see co-lead Aden Young exiting the show and Luke Kirby stepping in.

After a three-season run, Young’s character, Det. Sgt. Henry Graff has been relieved of duty.

The actor’s representatives say his contract was up, and although he enjoyed his time on the show, he was ready to move on.

A spokesperson for the production company, Cameron Pictures, says they were grateful for him bringing the character to life.

Filming is already underway in Toronto with a 10-episode Season 4 set to premiere this fall on Citytv.

Kirby, who won an Emmy for his role on “The Marvelous Mrs. Maisel,” will join returning cast members Kathleen Munroe, Karen Robinson, and K.C. Collins.

The Hamilton-born actor will play Det. Sgt. John Darcy — who is brought in from the guns and gangs division into homicide.

His credits also include the TV series “Dr. Death,” the Sarah Polley film “Take This Waltz,” and the critically acclaimed series “Rectify,” which he starred in alongside Young.

This report by The Canadian Press was first published May 19, 2026.