I think the best way actually to criticize this performance is to examine much of its praise which it heavily received in 2008. Well it was constantly praised as a technical performance. Look at the way he holds his arms back in enthusiasm was one, the way he walked was another. Well I must say that actually detracted greatly from the performance in my view. Penn lack in Mystic River, but to an even fuller extent always seems to be far to self-aware of his performance.
I know some might say, hey but aren't you that guy who think Laurence Olivier is one greatest actors ever, he most certianly was an actor who knew the in and out of his performance, well in his best performances he never let the audience knew he knew, and brought it about naturally. Sean Penn on the other hand never seems to not let the audience know that he most certianly is acting in this performance.
Penn I never felt really attempted at much to show a greater inner depth of character, but rather like Langella in my view always played each scene as just an acting display. Sure he most certianly has his quiet scenes as Langella did, but like them they seemed much too tailored merely to be the quiet scenes, rather than more natural scenes to show the range of the character.
I was never very convinced by Penn portrayal of Milk becuase of this, and I always felt it to be a very on the surface performance, always caught up on making far too obvious of faces, and gestures in both his quiet and loud scenes. I also thought his portrayal really tried to focus on the flamboyant aspects of Milk, just to simply go hey look I'm Sean Penn playing Harvey Milk, isn't this performance completely different from my other performances.
Due to this fact I always felt he played Milk in a rather stereotypical fashion, that always seemed rather awkward and unnatural to me. Milk's relationship with James Franco's character, never seemed believable because frankly both actors in all of those scenes seemed too aware that they were playing homosexual characters, and they themselves were not.
Sean Penn's performance as Milk never goes beyond his external obvious acting in my book. I think this is partially to blame the film as well, which perhaps also looks as Milk as a fairly surface documentary subject, rather than trying to completely get into the real depth of the character. Well perhaps the film believed Penn would do that, well for me though he never did that in the least.
