Leonardo DiCaprio
William 'Billy' Costigan, Jr.
Matt Damon
Staff Sgt. Colin Sullivan
Jack Nicholson
Francis 'Frank' Costello
Mark Wahlberg
Staff Sgt. Sean Dignam
Vera Farmiga
Dr. Madolyn Madden
Martin Sheen
Capt. Oliver Charles Queenan
Ray Winstone
Mr. Arnold 'Frenchy' French
Anthony Anderson
Trooper Brown
Alec Baldwin
Capt. George Ellerby
Kevin Corrigan
Cousin Sean
James Badge Dale
Barrigan
David O'Hara
Fitzy
Mark Rolston
Delahunt
Robert Wahlberg
Lazio (FBI)
Kristen Dalton
Gwen
Thomas B. Duffy
Govenor
Richard Hughes
Uncle Edward
J.C. MacKenzie
Realtor
Mary Klug
Billy's Aunt
Peg Holzemer
Mrs. Kennefick
Robert 'Toshi' Kar Yuen Chan
Triad Boss
Gurdeep Singh
Pakistani Proprietor
Armen Garo
Providence Gangster #1
John Cenatiempo
Providence Gangster #2
Joseph Riccobene
Kneecapped Bankrobber
Billy Smith
Detective #1 Tailing Queenan
Lyman Chen
Translator
Kevin P. McCarthy
Detective #1 - Colin's Unit
Chris Fischer
Detective #2 - Colin's Unit
Brian Smyj
Man Glassed in Bar
William Severs
Older Priest
Larry Mitchell
Younger Priest
Anthony Estrella
Police Camera Tech
Andrew Breving
Police Cell Phone Tech
Tracey Paleo
Darlene the Secretary
Douglas Crosby
Man Killed by French
Dorothy Lyman
Woman at Bar #1
Audrie Neenan
Woman at Bar #2
Frank Mallicoat
News Anchor
Paula DeMers
Billy's Mother
Conor Donovan
Young Colin
Amanda Lynch
Carmen
Sallie Toussaint
Woman at Opera
Patrick Coppola
Bookie Harassed by French
Mick O'Rourke
Jimmy Bags
Deborah Carlson
Sister Mary Theresa
Nellie Sciutto
Queenan's Secretary
Peter Welch
Other Prisoner
Henry Yuk
Chinese Government Man
Dennis Lynch
Costello's Crew #1
Michael Byron
Costello's Crew #2
William Lee
Costello's Crew #3
John Rue
Luncheonette Proprietor
Peter Crafts
Man in Costello's Bar
Joseph P. Reidy
Priest with Young Colin
John Farrer
Priest at Billy's Funeral
Paris Karounos
Jimmy Pappas
Brian Haley
Detective #2 Tailing Queenan
Terry Serpico
Detective #3 Tailing Queenan
Jay Giannone
Detective #4 Tailing Queenan
John Polce
Lynn Detective
Bo Cleary
Drill Instructor #2 (voice)
David Conley
Gang Member with Mr. French
Victor Chan
Chinese Delivery Man
Jill Brown
Executed Woman
Sarah Fearon
French's Wife
Denece Ryland
Woman Doctor
Zachary Pauliks
Young Billy
Daniel F. Risteen, Jr.
Crack House Cop #1
Francis P. Hughes
Crack House Cop #2
Johnny Cicco
Crack Addict
Chance Kelly
Exam Instructor
Shay Duffin
Bartender at Brasserie
John McConnell
Bookie in Costello's Bar
Kenneth Stoddard
State Trooper #1
Jeffrey Winter
State Trooper #2
Paddy Curran
New Guy
Mark Philip Patrick
New Guy
David Fischer
Executed Man
Walter Y.F. Wong
Waiter in Alley
Tony M. Yee
Waiter in Alley
Francesca Scorsese
Little Girl at Airport
Alex Morris
Young Man at Airport
Emma Tillinger Koskoff
Woman with Dog
Craig 'Radioman' Castaldo
Crack House Denizen
Takumi Bando
Triad (uncredited)
Eric Bruno Borgman
Reporter (uncredited)
Brendan Burke
Irish Thug (uncredited)
Chris Chinn
Gang Member (uncredited)
Jeffrey Corazzini
Crime Scene Unit (uncredited)
Jim Ford
Cadet (uncredited)
Trudi Goodman
Woman Office Worker (uncredited)
Steve Lord
Academy Pistol Coach (uncredited)
Jack McCullough
EMT (uncredited)
Osmani Rodriguez
Reporter (uncredited)
Lawrence Cameron Steele
Academy Firearms Instructor (uncredited)
Conor Timmis
Rugby Fan (uncredited)
Joseph Oliveira
Officer (uncredited)
Adam Masnyk
Southie Teen / Soccer Player (uncredited)
John Franchi
Pedestrian (uncredited)
Paul McGillicuddy
Subway Passenger (uncredited)
Kim Carrell
MA State Police Detective