Matthew Rhys Perry Mason Actor, Producer Juliet Rylance Della Street Actor Chris Chalk Paul Drake Actor Shea Whigham Pete Strickland Actor Eric Lange Gene Holcomb Actor Justin Kirk Hamilton Burger Actor Diarra Kilpatrick Clara Drake Actor Katherine Waterston Ginny Aimes Actor Tatiana Maslany Sister Alice Actor John Lithgow Elias Birchard "E.B." Jonathan Actor Rolin Jones Producer Ron Fitzgerald Producer Robert Downey Jr. Producer Susan Downey Producer Timothy Van Patten Producer