To Kill a Mockingbird 1962
His film debut, cast on Horton Foote's recommendation. No lines, and he doesn't appear until the end, but Letts calls Boo Radley deceptively hard: 'You have to convey a lot in a short amount of time with no lines.' White pallor, shock of white hair, haunted. 'He looks like a ghost,' and he never looked that way again.