| Steve Buscemi | Enoch 'Nucky' Thompson |
| Kelly Macdonald | Margaret Thompson |
| Michael Shannon | Nelson Van Alden |
| Shea Whigham | Elias 'Eli' Thompson |
| Michael Stuhlbarg | Arnold Rothstein |
| Stephen Graham | Al Capone |
| Vincent Piazza | Lucky Luciano |
| Michael Kenneth Williams | Chalky White |
| Anthony Laciura | Eddie Kessler |
| Paul Sparks | Mickey Doyle |
| Jack Huston | Richard Harrow |
| Charlie Cox | Owen Sleater |
| Bobby Cannavale | Gyp Rosetti |
| Gretchen Mol | Gillian Darmody |
| Billy Magnussen | Roger McAllister |
| Ivo Nandi | Joe Masseria |
| Ashlie Atkinson | Gianconda Rosetti - Gyp's Wife |
| Richard Barlow | Jack Corbett - Sagorsky's Neighbor |
| Mark Borkowski | Paul Sagorsky |
| Chris Caldovino | Tonino Sandrelli |
| Kevin Csolak | William Thompson |
| Judy Del Giudice | Malfada - Gyp's Mother |
| Lo Freidenstine | Anne Thompson |
| Josie Gallina | Emily Schroeder |
| Lucy Gallina | Emily Schroeder |
| Madeline Getty | Nora Thompson |
| Emma Holzer | Edith Thompson |
| Kate Loprest | Corrine - Artemis Club Girl |
| Clem McIntosh | Wellman - WWI Veteran |
| Declan McTigue | Teddy Thompson |
| Rory McTigue | Teddy Thompson |
| Brady Noon | Tommy Darmody |
| Connor Noon | Tommy Darmody |
| Glenn Peters | Priest |
| Charlie Plummer | Michael Thompson |
| Wrenn Schmidt | Julia Sagorsky |
| Jim Schubin | Phil Gardner - WWI Veteran |
| Mark Stolzenberg | Carnival Photographer |
| Nisi Sturgis | June Thompson |
| Brandon Zumsteg | Brian Thompson |
| Anne Bergstedt | Gillian's Prostitute |
| John Buscemi | Bodyguard |
| Kylie Cast | Middle Class Girl |
| Carina Castagna | Middle Class Girl |
| Nick Diamantis | Rosetti Thug |
| David Itchkawitz | Upscale Citizen |
| Logan Kulick | Working Class Son |
| Chloe Elaine Scharf | Working Class Daughter |
| Natasha Tax | Working Class Girl |