Boardwalk Empire is an HBO period drama focusing on Enoch “Nucky” Thompson (Steve Buscemi, The Sopranos), a political figure who rose to prominence and controlled Atlantic City, New Jersey, during the Prohibition period of the 1920s and 1930s. Nucky interacts with several historical figures in both his personal and political life, including mobsters, politicians, government agents, and the common folk who look up to him. The federal government also takes an interest in the bootlegging and other illegal activities in the area, sending agents to investigate possible mob connections but also looking at Nucky’s lifestyle—expensive and lavish for a county political figure. Primetime Emmy Award-winning screenwriter and producer Terence Winter (The Sopranos) created the show inspired by the book Boardwalk Empire: The Birth, High Times, and Corruption of Atlantic City by Nelson Johnson about historical criminal kingpin Enoch L. Johnson.
The pilot episode, directed by Martin Scorsese, was produced at a cost of $18 million. Boardwalk Empire has received widespread critical acclaim, particularly for its visual style and basis on historical figures, as well as for Buscemi’s lead performance. The series has received forty Primetime Emmy Award nominations, including two for Outstanding Drama Series, winning seventeen. The series has also won the Golden Globe Award for Best Television Series – Drama in 2011 and two Screen Actors Guild Awards for Outstanding Performance by an Ensemble in a Drama Series in 2011 and 2012.
- Steve Buscemi (The Sopranos, 30 Rock, Nurse Jackie) as Enoch “Nucky” Thompson (seasons 1–5) – the corrupt treasurer of Atlantic County and its most powerful political figure. Based on Atlantic City political boss Enoch L. Johnson.
- Michael Pitt (Hannibal) as James “Jimmy” Darmody (seasons 1–2) – Nucky’s onetime protegé, an honor student who left Princeton to serve in World War I; works briefly for Nucky before striking out on his own into organized crime.
- Kelly Macdonald (State of Play) as Margaret Thompson (seasons 1–5) – a young widow and mother, she turns to Nucky and becomes his mistress, and later his wife.
- Michael Shannon as Nelson Van Alden / George Mueller (seasons 1–5) – a former Prohibition Agent on the run. Under the alias “George Mueller,” he is a bootlegger in the Chicago area working as the muscle for Dean O’Banion’s organization, as well as Johnny Torrio’s organization.
- Shea Whigham (Agent Carter) as Elias “Eli” Thompson (seasons 1–5) – Nucky’s younger brother and former sheriff of Atlantic County. Now works as part of Nucky’s organization. Based on Alf Johnson.
- Michael Stuhlbarg (The American Experience) as Arnold Rothstein (seasons 1–4) – a powerful New York gangster who does business with Nucky. Charlie Luciano, Meyer Lansky and Benjamin Siegel work for him.
- Stephen Graham (This is England ’86, This is England ’88) as Al Capone (seasons 1–5) – a violent Chicago gangster who is the right-hand man of Chicago crime boss Johnny Torrio.
- Vincent Piazza (Rescue Me, The Sopranos) as Charles “Lucky” Luciano (seasons 1–5) – a New York gangster and associate of Rothstein.
- Paz de la Huerta as Lucy Danziger (seasons 1–2) – Nucky’s former mistress.
- Michael Kenneth Williams (The Wire) as Albert “Chalky” White (seasons 1–5) – a powerful African-American gangster in Atlantic City.
- Anthony Laciura as Edward Anselm “Eddie” Kessler (seasons 1–4) – Nucky’s loyal butler.
- Paul Sparks (Underemployed) as Mieczyslaw “Mickey Doyle” Kuzik (seasons 1–5) – an Atlantic City bootlegger.
- Dabney Coleman (The Guardian) as Commodore Louis Kaestner (seasons 1–2) – Nucky’s mentor and predecessor in Atlantic City; Jimmy’s father. John Ellison Conlee portrays a young Commodore in the season 5 flashbacks.
- Jack Huston (Eastwick) as Richard Harrow (recurring season 1; regular seasons 2–4) – a former Army marksman who allies with Jimmy. Disfigured in the war, he wears a tin mask over half of his face.
- Gretchen Mol (Life on Mars) as Gillian Darmody (recurring season 1; regular seasons 2–5) – Jimmy’s mother and Nucky’s longtime friend.
- Charlie Cox (Daredevil) as Owen Sleater (recurring season 2; regular season 3) – an IRA volunteer who works for Nucky; also having an affair with Margaret.
- Bobby Cannavale (Third Watch, Will & Grace, Nurse Jackie) as Gyp Rosetti (season 3) – a ruthless gangster who challenges Nucky.
- Ron Livingston (The Practice, Standoff, Defying Gravity) as Roy Phillips (season 4) – a Pinkerton detective that poses as a wealthy out-of-town businessman who gets involved with Gillian Darmody in order to prosecute her for murder.
- Jeffrey Wright (Westworld) as Dr. Valentin Narcisse (seasons 4–5) – a Harlem-based philanthropist and “Doctor of Divinity”, who plans to take over the heroin trade in Atlantic City. The character was inspired by Casper Holstein.