Michael Sheen
Dr. Slavkin O'Hara
Toni Collette
Patricia Herman
Jason Spevack
Henry James Herman
Samantha Weinstein
Audrey O'Hara
Melyssa Ade
Kindergarten Teacher
Oprah Winfrey
Oprah
Frank Moore
Stan Herman
Paul Braunstein
Dr. Gunther Flowers
Hannah Brigden
Young Patricia Herman
Sarah Orenstein
Mother Herman
Jamie Johnston
Young Billy Herman
Mark MacDonald
Tim Herman
Mickey MacDonald
Tom Herman
Cameron Kennedy
Jimmy Herman
Kate Hewlett
Alice O'Hara
Kevin Hare
Delivery Room Doctor
Austin Macdonald
Brian the Bully
Mishu Vellani
Miss Abda
Aaron Abrams
Malcom's Dad / Nurse Stewart