11. 'Shutter Island' (2010)
DiCaprio's work with Martin Scorsese has always centered around obsession, and this noirish mystery is their most haunted film yet — as well as the most vulnerable the actor has ever been. He plays an investigator looking into the disappearance of a cryptic inmate at a creepy island insane asylum. As he delves further into the case, however, his own psyche starts being called into question. So DiCaprio not only has to carry the narrative, but he also has to tear down his character as the film proceeds. To keep us watching while fostering such uncertainty is the mark of a truly great actor.