Jensen Ackles
Off the top of my head, he's an actor that looks most like James Dean.
sharenot physically.
Jensen could have played James Dean in a play for theater when he was younger. Acting chops are there, looks not so much like James.
Hmm . . . I can't see even the slightest resemblance between the two.
JA is way too old, way too tall, and, honestly, way too traditionally handsome to play James Dean.
No physical similarities except the 'white male' factor.
Remember, always be yourself.
Unless you suck.
-- Joss Whedon
Too old and his voice is too deep
We try but we didn't have long
We try but we don't belong...
-Hot Chip (Boy from School)