To take down South Boston's Irish Mafia, the police send in one of their own to infiltrate the underworld, not realizing the syndicate has done likewise. While an undercover cop curries favor with the mob kingpin, a career criminal rises through the police ranks. But both sides soon discover there's a mole among them.
as Billy
as Colin
as Costello
as Dignam
as Queenan
as Mr. French
as Madolyn
as Brown
as Ellerby
as Cousin Sean
as Barrigan
as Fitzy
as Delahunt
as Lazio (FBI)
as Gwen
as Govenor
as Uncle Edward
as Realtor
as Billy's Aunt
as Mrs. Kennefick
as Triad Boss
as Pakistani Proprietor
as Providence Gangster #1
as Providence Gangster #2
as Kneecapped Bankrobber
as Detective #1 Tailing Queenan
as Translator
as Detective #1 - Colin's Unit
as Detective #2 - Colin's Unit
as Man Glassed in Bar
as Older Priest
as Younger Priest
as Police Camera Tech
as Police Cell Phone Tech
as Darlene the Secretary
as Man Killed by French
as Woman at Bar #1
as Woman at Bar #2
as News Anchor
as Billy's Mother
as Young Colin
as Carmen
as Woman at Opera
as Bookie Harassed by French
as Jimmy Bags
as Sister Mary Theresa
as Queenan's Secretary
as Other Prisoner
as Chinese Government Man
as Costello's Crew #1
as Costello's Crew #2
as Costello's Crew #3
as Luncheonette Proprietor
as Man in Costello's Bar
as Priest w/ Young Colin
as Priest at Billy's Funeral
as Jimmy Pappas
as Detective #2 Tailing Queenan
as Detective #3 Tailing Queenan
as Detective #4 Tailing Queenan
as Lynn Detective
as Drill Instructor #2 (voice)
as Gang Member with Mr. French
as Chinese Delivery Man
as Executed Woman
as French's Wife
as Woman Doctor
as Crack House Cop #1
as Crack House Cop #2
as Crack Addict
as Exam Instructor
as Bartender at Brasserie
as Bookie in Costello's Bar
as State Trooper #1
as State Trooper #2
as New Guy
as New Guy
as Executed Man
as Waiter in Alley
as Waiter in Alley
as Little Girl at Airport
as Young Man at Airport
as Woman with Dog
as Crack House Denizen
as Triad (uncredited)
as Reporter (uncredited)
as Irish Thug (uncredited)
as Gang Member (uncredited)
as Crime Scene Unit (uncredited)
as Cadet (uncredited)
as Woman Office Worker (uncredited)
as Academy Pistol Coach (uncredited)
as EMT (uncredited)
as Reporter (uncredited)
as Academy Firearms Instructor (uncredited)
as Rugby Fan (uncredited)
as Officer (uncredited)
as Southie Teen / Soccer Player (uncredited)
as Pedestrian (uncredited)
as Subway Passenger (uncredited)
as MA State Police Detective
as Adult Film Actress (uncredited)