Aaron Staton (Mad Men) has been cast in a heavily recurring role on the third season of Showtime drama Ray Donovan. Staton will play Mr. Donellen, a strict yet kind high school teacher with a tragedy in his past.

The series stars Liev Schreiber as LA’s best professional fixer, the man called in to make the city’s celebrities, superstar athletes, and business moguls’ most complicated and combustible situations go away. In Season 2, Ray’s life erupted when the FBI, his father Mickey (Jon Voight), and his own family slip out of his control, testing his roles as protector, provider and patriarch like never before. Also joining Season 3 are Katie Holmes, Guy Burnet, Fairuza Balk and Shree Crooks. Ray Donovan was created by Ann Biderman and is executive produced by David Hollander, Mark Gordon and Bryan Zuriff.

Staton is repped by ICM Partners and Sanders Armstrong Caserta Management.