Leonardo DiCaprio .... Billy Costigan
Matt Damon .... Colin Sullivan
Jack Nicholson .... Frank Costello
Martin Sheen .... Oliver Queenan
Vera Farmiga .... Madeleine
Mark Wahlberg .... Dignam
Anthony Anderson .... Brown
Ray Winstone .... Mr. French
Alec Baldwin .... Ellerby
rest of cast listed alphabetically:
Douglas J. Aguirre .... NYPD Ceremonial Guard
Robert N. Anderson .... Cadet
Andrew Aninsman .... Undercover Narcotics Detective
Michael Arthur .... SIU Detective #1
Ricardo Azulay .... Featured Extra
Dion Baia .... Donegan
Vincent Bivona .... Cadet
Tracey Brennan .... E.R Doctor
Andrew Breving .... Phone Tech
Brendan Burke .... Rookie Thug
Kevin W. Burns .... Cadet Moss
Michael Byron .... Costello Crew
John Cenatiempo .... Guinea
Robert 'Toshi' Kar Yun Chan .... Triad Boss
Lyman Chen .... Robert Yan
Johnny Cicco .... Sad Sack of Shit
Bo Cleary .... State police drill instructor
David Conley .... Irish Thug
Greg Connolly .... Undercover Cop
Patrick Coppola .... The Bookie
Kevin Corrigan .... Christopher
Derrick Costa .... Officer Doorley
Peter Crafts .... Jimmy the drinker
James Badge Dale
Kristen Dalton .... Gwen
Elizabeth Dings .... Reporter
Conor Donovan .... Young Colin
Shay Duffin .... Jimmy
Anthony Estrella .... Tech Cop
Chris Fischer .... SIU Detective
Steve Flynn .... Detective
Shawn Fogarty .... Businessman on street
Armen Garo .... Guinea #1
Brian Haley .... Detective Flynn
Frank Hansen .... Police Cadet in classroom
Eli Harris .... Cadet #2
Tyler Hollinger .... Cadet Core
Duncan Inches .... Photo stand in
Colleen Kelly .... Reporter
Tom Kemp .... William Costigan, Sr.
William Lee .... Costello's Crew
Ted R. Lewinski .... Cadet
Crystal Lisbon .... Business Woman
Gary Lockwood .... Jonny
Steve Lord .... Firearms Instructor
Amanda Lynch .... Carmen
Dennis Lynch .... Costello Crew #1
J.C. MacKenzie .... Building Manager
Oliver Martin .... State Trooper
Kevin P. McCarthy .... Detective
Denis McKeown .... Mourner
Chris McMullin .... Firearms Instructor
Johnny Mez .... FNG Gang Member
Larry Mitchell .... Younger Priest
Sheridan Murphy .... Rugby Girlfriend
David O'Hara .... Fitzy
Tracey Paleo .... Darleen
Zachary Pauliks .... Young Billy
Ruth Phelps .... Pedestrian
Jason Pierce .... State Trooper
John Polce .... Lynn policeman
Nick Psinakis .... Cadet
James Donnell Quinn .... Mass. State Trooper
Jerry Quinn .... Southie Neighbor
Bill Richards .... Driver
Osmani Rodriguez .... Reporter
Mark Rolston .... Delahunt
Shawn Russell .... Police Cadet
Nellie Sciutto .... Queenan's Secretary
Billy Smith .... Detective Reade
Brian Smyj .... Well Dressed Scumbag
Lawrence Cameron Steele .... Ballistics Instructor
Steve Tarantino .... State Trooper
Conor Timmis .... Rugby fan
Sallie Toussaint .... Woman At Opera
Village .... Detective
Robert Wahlberg .... FBI agent Joyce
Danny Whooley .... Boy at Fair
Douglas C. Williams .... S.I.U. Detective
Mike Wilson .... Cadet