Billy
Colin
Costello
Dignam
Queenan
Mr. French
Madolyn
Brown
Ellerby
Cousin Sean
Barrigan
Fitzy (as David Patrick O'Hara)
Delahunt
Lazio (FBI)
Gwen
Governor
Uncle Edward (as Dick Hughes)
Realtor
Billy's Aunt
Mrs. Kennefick (as Peg Saurman Holzemer)
Triad Boss (as Robert Chan)
Pakistani Proprietor
Providence Gangster #1
Providence Gangster #2
Kneecapped Bankrobber
Detective #1 Tailing Queenan
Translator
Detective #1 - Colin's Unit
Detective #2 - Colin's Unit
Man Glassed in Bar
Older Priest
Younger Priest
Police Camera Tech
Police Cell Phone Tech
Darlene the Secretary
Man Killed by French
Woman at Bar #1
Woman at Bar #2
News Anchor
Billy's Mother
Young Colin
Carmen
Woman at Opera
Bookie harassed by French
Jimmy Bags
Sister Mary Theresa
Queenan's Secretary
Other Prisoner
Chinese Government Man
Costello's Crew #1
Costello's Crew #2
Costello's Crew #3 (as Billy Lee)
Luncheonette Proprietor
Man in Costello's Bar
Priest with Young Colin (as Joseph Reidy)
Priest at Billy's Funeral
Jimmy Pappas
Detective #2 Tailing Queenan
Detective #3 Tailing Queenan
Detective #4 Tailing Queenan
Lynn Detective (as John J. Polce)
Drill Instructor #2 (voice)
Gang Member with Mr. French
Chinese Delivery Man
Executed Woman
French's Wife
Billy Costigan, Sr. (scenes deleted)
Woman Doctor
Young Billy (scenes deleted)
Crack House Cop #1
Crack House Cop #2
Crack Addict
Exam Instructor
Bartender at Brasserie
Bookie in Costello's Bar (as John M. McConnell)
State Trooper #1
State Trooper #2
New Guy
Executed Man
Waiter in Alley
Little Girl at Airport
Young Man at Airport
Woman with Dog (as Emma Tillinger)
Crack House Denizen (as Craig 'Radioman' Castaldo)
State Trooper (uncredited)
Boston Police Dignitary (uncredited)
Undercover Drug Agent (uncredited)
Bystander (uncredited)
Donegan - Police Cadet (uncredited)
Triad Gangster (uncredited)
Cadet #15 (uncredited)
Reporter (uncredited)
Boston Police Chief (uncredited)
E.R. Doctor (uncredited)
State Trooper Graduate (uncredited)
Irish Thug (uncredited)
Business Woman (uncredited)
Businessman (uncredited)
Driver of Car in Chase (uncredited)
Crime Scene Unit (uncredited)
Boston PD (uncredited)
Subway Passenger (uncredited)
Sean (uncredited)
Police Officer (uncredited)
Detective (uncredited)
Rugby Friend (uncredited)
State Police Detective (uncredited)
Pedestrian / Businessman (uncredited)
Cadet (uncredited)
Pedestrian (uncredited)
Extra (uncredited)
Woman Office Worker (uncredited)
Child at Carnival (uncredited)
College Student (uncredited)
Asian Triad (uncredited)
Academy Pistol Coach (uncredited)
Adult Film Actress (uncredited)
Inmate (uncredited)
Chinatown Shopper (uncredited)
Southie Teen / Soccer Player (uncredited)
EMT (uncredited)
Duffy (uncredited)
Cadet Parent (uncredited)
Officer (uncredited)
Daniel (uncredited)
Subway Rider (uncredited)
Cop (uncredited)
Construction Worker (uncredited)
Forensics Officer (uncredited)
Academy Firearms Instructor (uncredited)
Shopper in China Town (uncredited)
Minor Role (uncredited)
Waitress (uncredited)
Pedestrian / Driver (uncredited)
Restaurant Worker (uncredited)
Drug Dealer (uncredited)