Martin Scorsese Director Leonardo DiCaprio Billy Costigan Actor Matt Damon Colin Sullivan Actor Jack Nicholson Frank Costello Actor Mark Wahlberg Sgt. Dignam Actor Martin Sheen Capt. Queenan Actor Ray Winstone Mr. French Actor Vera Farmiga Madolyn Actor Alec Baldwin Capt. Ellerby Actor James Badge Dale Barrigan Actor David O'Hara Fitzy Actor Mark Rolston Delahunt Actor Kevin Corrigan Cousin Sean Actor Anthony Anderson Brown Actor Amanda Lynch Carmen Actor Tracey Paleo Darleen Actor Kristen Dalton Gwen Actor Tom Kemp Billy's father Actor Gary Lockwood Jonny Actor William Monahan Writer Brad Pitt Producer Brad Grey Producer Graham King Producer Roy Lee Executive Producer Gianni Nunnari Executive Producer Doug Davison Executive Producer G. Mac Brown Executive Producer Kristin Hahn Executive Producer Howard Shore Original Music Michael Ballhaus Cinematographer Thelma Schoonmaker Film Editing Kristi Zea Production Design Leslie E. Rollins Set Decoration Teresa Carriker-Thayer Art Director Nicholas Lundy Art Director Sandy Powell Costume Design Ellen Lewis Casting Alan Mak Screenwriter Felix Chong Screenwriter