Will Smith

as Dr. Bennet Omalu

Alec Baldwin

as Dr. Julian Bailes

Albert Brooks

as Dr. Cyril Wecht

Gugu Mbatha-Raw

as Prema Mutiso

David Morse

as Mike Webster

Arliss Howard

as Dr. Joseph Maroon

Mike O'Malley

as Daniel Sullivan

Eddie Marsan

as Dr. Steven DeKosky