Johnny Depp as James 'Whitey' Bulger

Joel Edgerton as John Connolly

Julianne Nicholson as Marianne Connolly

Dakota Johnson as Lindsey Cyr

Kevin Bacon as FBI Agent Charles McGuire

Benedict Cumberbatch as Billy Bulger

Peter Sarsgaard as Brian Halloran

Juno Temple as Deborah Hussey

Jesse Plemons as Kevin Weeks

David Harbour as John Morris

Adam Scott as FBI Agent Robert Fitzpatrick

Corey Stoll as Fred Wyshak

Bill Camp as John Callahan

Mark Mahoney as Mickey Maloney

Brad Carter as John McIntyre

Scott G. Anderson as Tommy King

Lonnie Farmer as DEA Agent Eric Olsen (Interrogator)

Mary Klug as Mom Bulger

Erica McDermott as Mary Bulger

Luke Ryan as Douglas Cyr

Owen Burke as Buddy Leonard

Lewis D. Wheeler as Jeremiah O'Sullivan

Billy Meleady as Joe Cahill

Jamie Donnelly as Mrs. Cody

David De Beck as Roger Wheeler

Gary Galone as State Captain

Rory Cochrane as Stephen Flemmi

James Russo as Agent Scott Gariola

Danae Nason as McGuire's Secretary

Bretton Manley as Young Boy

Berglind Jonsdottir as Anna Bjornsdottir

David Conley as Officer Flynn

Ciaran Crawford as Irish Nationalist

Thomas Philip O'Neill as FBI Wire Tech

Joey Vacchio as Joey, Big Italian

Bill Haims as Gennaro Angiulo

Anthony Molinari as Charlie McTiernan

Declan Mulvey as Charlie's Friend

Bates Wilder as Agent James

Marc Carver as Dick Lehr

Richard Donelly as Gerard O'Neill

Brian A. White as Prisoner

Peter Morse as FBI Agent

Tom Kemp as Father Mackey

Patrick M. Walsh as Michael Donahue

Naheem Garcia as DEA Agent

Kathryn A. Beauchamp as Nurse

Stephen Curran as Drug Dealer

Darin X.L. MacEachern as Drug Dealer

Cary 'Big Shug' Guy as Drug Dealer

Sean Malone as Crook

Jack Neary as Barman

Jimmy Joe Maher as Boot Shop Owner

Forry Buckingham as World Jai Alai Chairman

Danny DeMiller as Porthole Bartender

Michael F. Murphy as Porthole Customer

Alexander Cook as DEA Agent Dan Doherty

Ava Cooper as Little Mary Bulger

Stella Cooper as Kathleen Bulger

Arthur Hiou as Driver

Todd Ryan Jones as Charlie's Friend

Julie Ann Dawson as Floor Dancer (uncredited)

Fergaledgar as Trevor Williams (uncredited)

Robert E. Walsh as Sr. FBI Official (voice)

W. Earl Brown as John Martorano

Jim Powers as The Mayor

Jeff Kamps as Walker

Susan Garfield as Press Photographer

Colleen Kelly as Marion Hussey (uncredited)