Steve Buscemi Enoch "Nucky" Thompson Actor Kelly Macdonald Margaret Schroeder Actor Michael Shannon Nelson Van Alden Actor Shea Whigham Elias Thompson Actor Stephen Graham Al Capone Actor Vincent Piazza Lucky Luciano Actor Paul Sparks Mickey Doyle Actor Michael Kenneth Williams Chalky White Actor Gretchen Mol Gillian Actor Dominic Chianese Leander Whitlock Actor Arron Shiver Dean O'Banion Actor Stephen Root Gaston Means Actor Jeffrey Wright Dr. Valentin Narcisse Actor Ron Livingston Roy Phillips Actor Patricia Arquette Sally Wheet Actor Brian Geraghty Agent Warren Knox Actor Domenick Lombardozzi Ralph Capone Actor Morgan Spector Frank Capone Actor Jim True-Frost Eliot Ness Actor Matt Letscher Joseph Kennedy Actor Giampiero Judica Salvatore Maranzano Actor Louis Cancelmi Mike D'Angelo Actor Terence Winter Executive Producer Martin Scorsese Executive Producer Timothy Van Patten Executive Producer Stephen Levinson Executive Producer Mark Wahlberg Executive Producer