9. Jack Nicholson - The Departed
In a role that was loosely based around real-life Irish kingpin Whitey Bulger, Jack Nicholson explodes off the screen as Frank Costello, the leader of the Boston Irish mob in The Departed. Nicholson, an actor known for always playing it cool, keeps the malevolence of Costello's violent nature bubbling at the surface and plays the role with a brash confidence. Costello lives the good life, he enjoys opera, orgies and slicing up a body when the mood strikes him, and nobody could have played the part so well as Jack Nicholson. His character connects both intertwining story lines in the film involving co-stars Matt Damon and Leonardo Dicaprio, and he wrangles both actors in with his unpredictable character work, making their performances better and his shine. Jack Nicholson, who is now in semi-retirement, is one of the greatest American film actors of all-time.