Though he is not without competition, the best of the film's male actors is DiCaprio. Moviegoers used to his eternal boyishness will be pleasantly surprised at this, his first fully adult role, at the genuine substance and maturity he brings to this part without losing any of his trademark vulnerability. As Scorsese told Entertainment Weekly, "his face is a battlefield of moral conflicts."
Another revelation for some viewers will be the critical performance of Farmiga as Madolyn, a psychiatrist with links to both Costigan and Sullivan. An actress who has been quietly knocking roles out of the park for half a dozen years, Farmiga handles this tricky part with aplomb, convincingly bringing different emotions to her scenes with both men. It would be a heck of an irony if this super-macho film was remembered as the one where this splendid actress finally got her due.