Main

• Jordana Spiro as Grace Devlin; well-educated doctor and surgical resident who took on her brother's debt to the mob.
• William Forsythe as Constantine Alexander; returned Chicago Outfit boss and Grace's protector.
• James Carpinello as Franco Leoni; Constantine's enforcer and Grace's ex-boyfriend. Undercover FBI agent working to bring down the Chicago mob.
• Zach Gilford as Brett Robinson; Grace's boyfriend to whom she has to lie at times to protect her secrets.
• Željko Ivanek as Stafford White, Chief of Surgical Department; supervises Grace, favors her as a promising surgeon.
• Floriana Lima as Rosa "Ro" Quintero; nurse at the hospital and friend of Grace.
• Jaime Lee Kirchner as Olivia Watson; rival doctor working in the same surgical unit residency as Grace.
• Wendy Makkena as Daniella Devlin, mother of Grace and Nate; she has a history with Constantine.
• Jesse Lee Soffer as Nate Devlin, Grace's brother; owed a debt to mob boss Paul Moretti but his sister took it on for him. Works in Constantine's crew after Moretti is overthrown.

Recurring

• Michael Rapaport as Paul Moretti, former leader of the mob until Constantine takes over.
• David Pasquesi as Ian Fanagan, a senior colleague of Grace's, who Grace frequently disagrees with.
• Kevin J. O'Connor as Stavos Kazan, personal attorney to and consigliere of Constantine's mob family.
• Adam J. Harrington as Owen York, an FBI agent investigating Constantine.
• Shohreh Aghdashloo as Jayana Baylor, a senior doctor at the hospital.
• Kevin Corrigan as Titus Amato, an acquaintance of Constantine and new business partner in the poker machine business.
• Terry Kinney as Donte Amato, brother of Titus, friend of Constantine, and knew Grace's father.
• Jennifer Beals as Celeste LaPree, a madam standing as a proxy for a mob boss in Constantine's underground circle.
• Mike Starr as Al Trapani, a member of Constantine's underground circle.
• Michael Madsen as Russell King, an associate of one of Constantine's former rivals, who attempted to take over Downtown Chicago, before being out-muscled by Constantine.

Critical response

The show has been met with "mixed or average" reviews, with a collective score of 42/100 from Metacritic.^[27] Mary McNamara of the Los Angeles Times gave the show a neutral rating, observing that 'Despite the frantic and at times clunky initial execution, there are times when The Mob Doctor shows signs of transcending the typical doc-with-something-extra medical procedural'.^[28] Linda Stasi of the New York Post gave the show one and a half stars, saying, "They tried for the tried and true, hoping they'd get The Sopranos meets Grey's Anatomy while filling the hole House left in the schedule. And, like a camel, they ended up with an animal made by committee."^[29] David Wiegand of the San Francisco Chronicle gave the show a 0 rating, saying, "The two-taste-treats-in-one thing worked for Hostess Ding-Dongs, so maybe Fox figured it would work for this ding-dong of a dud for the masochists in the crowd".^[30]

A few critics, however, had favorable reviews. Glenn Garvin of the Miami Herald praised the concept of the show, saying, "Devlin's complex relationship with the gangsters is what elevates The Mob Doctor into something a cut or two above a Grey's Anatomy rip-off". Diane Werts of Newsday noted that "No, it's not exactly House. But it isn't like any other show, either, with its mad mix of moral dilemmas, medical crises, family ties, double-life-living and, y'know, rubouts 'n' stuff"

Ratings