- 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
- 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
- William Severs - Older Priest
- Larry Mitchell - Younger Priest
- Anthony Estrella - Police Camera Tech
- Tracey Paleo - Darlene the Secretary
- Dorothy Lyman - Woman at Bar #1
- Audrie Neenan - Woman at Bar #2
- Deborah Carlson - Sister Mary Theresa
- Nellie Sciutto - Queenan's Secretary
- 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
- John Farrer - Priest at Billy's Funeral
- Brian Haley - Detective #2 Tailing Queenan
- Terry Serpico - Detective #3 Tailing Queenan
- Jay Giannone - Detective #4 Tailing Queenan
- Bo Cleary - Drill Instructor #2 (voice)
- David Conley - Gang Member with Mr. French
- Denece Ryland - Woman Doctor
- Johnny Cicco - Crack Addict
- Chance Kelly - Exam Instructor
- Shay Duffin - Bartender at Brasserie
- John McConnell - Bookie in Costello's Bar
- Paddy Curran - New Guy
- Francesca Scorsese - Little Girl at Airport
- 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
- Rebecca Love - Adult Film Actress (uncredited)
- Martin Scorsese
- Joseph P. Reidy
- G. A. Aguilar
- Felix Chong
- Brad Grey
- Brad Pitt
- Roy Lee
- Emma Tillinger Koskoff
- Graham King
- Ellen Lewis
- Howard Shore
- Marko Costanzo
- Marissa Littlefield
Capítulo disponible en las siguientes plataformas:
