Michael Sullivan, Sr.
A top-notch hitman who works for John Rooney.
- Anti-Hero: An darker example. He intends to save his son's soul so he couldnt be ended up like him through pragmatic means.
- Badass and Child Duo: He's the badass to his son's Child.
- Badass Longcoat: He's usually seen wearing one of these.
- Contract on the Hitman: He works as Rooney's right-hand man and top killer, only for Rooney and Nitti to put a hit on him because he won't give up his vendetta against Connor for killing his wife and son.
- The Dragon: To John Rooney, as Rooney's right-hand man and enforcer.
- The Dreaded: The name Sullivan carries quite a bit of weight in the criminal underworld.
- Even Evil Has Loved Ones: He's a hitman as well as a loving father and husband.
- Everyone Has Standards: Even though he's a mob enforcer that doesn't mean he's completely abandoned his moral code. He calls out Connor for murdering Finn McGovern when they were just ordered to talk with him, and when he robs a mob bank, he threatens the manager that he better not find out he just took the savings of starving farmers.
- Evil Parents Want Good Kids: He'll damn his own soul to Hell if it means saving his son's soul.
- The Hero Dies: He succeeds in getting his revenge against Connor Rooney, and Nitti agrees to call off the hit on him. Only for Maguire to mortally wound him anyway as revenge for disfiguring his face. Sullivan lives just long enough to save his son and kill Maguire before succumbing to his wounds.
- Hitman with a Heart: He'll kill on Rooney's orders but he obviously doesn't relish doing so, and he's motivated by a desire to ensure his children don't end up like him.
- More Dakka: His heavy weapon is a Tommy gun.
- Outliving One's Offspring: Connor kills his younger son, Peter, mistaking him for Michael Jr.
- Patricide: Killing his Parental Substitute John Rooney.
- Revenge Before Reason: He has many opportunities to just leave with his son but, ultimately, is unable to let go of his need for revenge.
- Robbing the Mob Bank: After Maguire makes his first attempt to kill him, he starts robbing banks for their dirty money only in the hopes that threatening their profits will convince Capone to give up Connor.
- Too Much Alike: His reason given for why he subconsciously treated his elder son differently than Peter. Michael Jr. reminded him too much of himself and he didn't want him to end up like him.
- Walking Armory: He usually brings a Tommy gun, a Colt M1911 semi-automatic, and a Colt Detective Special as a backup weapon.
- "Well Done, Son!" Guy: His sons have this dynamic with him and Sullivan has this dynamic with Rooney, his surrogate father. All his criminal efforts are a means to pay Rooney back for everything Rooney's done for him.
- White Shirt of Death: Wears a white shirt when he is killed by Harlen Maguire.
- You Remind Me of X: He tells Michael Jr. that he treated him differently because he reminded Sullivan of himself.
Michael Sullivan, Jr.
Michael Sullivan's son.
A crime boss who treats Sullivan as a surrogate son.
- Affably Evil: He's respectful towards everyone he deals with and tries to avoid unnecessary bloodshed whenever possible. He truly doesn't want Sullivan dead, and only orders a hit on him because he loves his son too much to let Sullivan kill him.
- Beware the Nice Ones: Even though he's a crime boss, his soft-spoken, affable and understanding nature practically makes him a Reasonable Authority Figure. However, he's still a crime boss so he has no problem ordering hits when he thinks it necessary, even if it's against his surrogate son.
- Big Bad: The source of much of the conflicts in the film, such as Mike Sr.'s corruption years ago, Connor's Daddy Issues, and hiring Harlen Maguire.
- Cool Old Guy: Behaves as a kindly grandfather to Mike's children.
- The Don: He's an Irish crime boss allied with the Chicago Mob who rules his town like a god.Finn McGovern: You rule this town as God rules the Earth. You give, and you take away.
- Even Evil Has Loved Ones:
- Despite all of his screw-ups, Rooney loves his biological son, Connor, and will do anything to protect him from Sullivan's wrath. Even when Sullivan reveals Connor has betrayed Rooney by stealing from him for years, he still won't give up his son.
- Even though he ends up ordering a hit on his surrogate son, Sullivan, to protect Connor, it's clear he still cares about him and tries to give him every opportunity to let the grudge die so Rooney can spare his life. When Sullivan comes to kill him, Rooney tells him he's happy he's the one doing it.
- Even Evil Has Standards: He orders a hit on his surrogate son, Sullivan, to protect his biological son from his wrath. However, he refuses to order a hit against Michael Jr., regardless of the threat he could pose in the future or what he's seen, because he's a child.
- Evil Old Folks: An old Don who is still a large presence in the criminal underworld.
- Face Death with Dignity: When he realizes that Sullivan's comes to kill him, he just bows his head in resignation as his men are gunned down, then turns around and tells his surrogate son that he's glad Sullivan is the one to kill him.
- "Facing the Bullets" One-Liner: "I'm glad it's you."
- Honor Before Reason: He won't give up his son, no matter how justified Sullivan is in his vendetta or how much easier it would make Rooney's life overall.
- I Wished You Were Dead: When he finds out what Connor did to the Sullivans, he begins beating him while saying he curses the day Connor was born, before realizing what he's just said and hugging him in remorse.
- No-Holds-Barred Beatdown: Inflicts one on Connor when he discovers what his son did to Annie and Peter. Complete with Punctuated Pounding.Connor: Pa, I'm sorry.John: Stupid!Connor: The kid would have talked. I'm sorry.John: Goddamn you. Goddamn you! (punch) I curse... (punch) The f***ing... (punch) Day! (punch) You were born. I Curse it!
- Parental Substitute: He's treated Michael Sr. like a son, explaining the latter's loyalty to him.
- Thicker Than Water: Despite what Connor has done, he still protects him.
- This Is Gonna Suck: "Lord help us."
- "Well Done, Son!" Guy: He's the father figure that his biological son, Connor, and surrogate son, Sullivan, both try to impress.
- Would Not Hurt A Child: He refuses to put a hit out on Michael Jr. despite the risk he poses.
A crime scene photographer who moonlights as an assassin.
- Bald of Evil: The hair's thinning on the top of his head and he is an amoral Professional Killer.
- Composite Character: There was no single hitman after the Sullivans in the graphic novel, with them simply having to deal with various cardboard bad guys. Its writer admitted creating a single character for this purpose was a big improvement.
- Creepy Souvenir: The photographs he takes of the murders he's committed.
- Dragon Their Feet: Technically he's Nitti's dragon, but he's the final threat faced in the film who kills Sullivan after Rooney and Connor have been dealt with.
- Establishing Character Moment: He arrives as his legitimate job as a crime scene photographer to take pictures of a dead man. When he's alone, it's revealed the victim is still alive, so Maguire calmly suffocates him to death so he can carry on with his pictures.
- Famous Last Words: "Come on, give me the gun."
- Faux Affably Evil: Seems quite cordial with Mike before he makes his intentions known.
- Hero Killer: Murders Mike Sullivan Sr. at the end of the film.
- It's Personal: He kills Mike Sr. even after the hit is called off because he scarred his face.
- Mad Artist: To an extent. In addition to assassination, he also takes pictures of his victims which he both sells to make extra money and keeps as part of his personal gallery.
- Psycho for Hire: He's an assassin with a fascination with death to the point that he doubles as a crime scene photographer so he can take pictures of the dead and dying. In a conversation with Sullivan, he says he's lucky to do what he loves for a living.
- Shotguns Are Just Better: Wields a shotgun during the hotel shootout.
- Unfriendly Fire: Accidentally kills Alexander Rance in the hotel shootout.
The unstable, violent son of John Rooney. He is jealous of the surrogate relationship between his father and Sullivan.
- All for Nothing: He killed the McGoverns and the Sullivans to cover up the fact that he's been stealing from his father. However, his father already knew, and all Connor's actions did was ensure his death and Rooney's own.
- Deadly Bath: Given a Boom, Headshot! by Michael Sr. while in a bathtub.
- Evil Is Petty: Tries to murder Michael Jr. just because he thinks the boy will rat him him out, even though Michael Sr. has sworn his son to secrecy.
- Green-Eyed Monster: His jealousy of Michael Sr. is at the core of his issues.
- He Knows Too Much: In order to cover up the fact that he's been stealing from his father, Connor tries to have Sullivan killed and personally goes to murder Michael Jr., killing Annie Sullivan in the process, because they know too much. The only reason Michael Jr. survives is because Connor mistakes Peter for him. And for additional irony his father knew all along that Connor had been stealing from him, so the deaths were completely pointless.
- Inadequate Inheritor: He's next in line to inherit his father's criminal organization when he passes on, but compared to his father he's incompetent and unstable to the point where Nitti gives him up to Sullivan after Rooney's killed.
- Karmic Death: Murdered Annie and Peter while the latter was taking a bath. Michael Sr. kills Connor the same way.
- Murder Is the Best Solution: Killing people is Connor's preferred way of handling problems. Despite how useful they are to his father, Connor kills the McGoverns and the Sullivans when he thinks they could be an inconvenience.
- Psychopathic Manchild: Of the whiny, petulant type. Just see him whimpering and cowering when his father learns what Connor did to Annie and Peter Sullivan.
- Psychotic Smirk: Which does him no favors when his father asks for an apology at a meeting.John: You would like to apologize? Try again.
- Stealing from the Till: He's been stealing money from his father via people he's killed, like the McGoverns.
- Stepford Smiler: He tries to be in the beginning at least, where he masks his instability and resentment behind a weak grin and awkward jokes. Peter even asks why Connor's always smiling and gets this in response.Connor: (furiously) Because it's all so fucking hysterical.
- Surprisingly Sudden Death: He's a major antagonist who Sullivan spends most of the movie trying to kill out of vengeance for his murdered wife and son. However, Connor's actual death is highly anticlimactic in how abrupt it is, especially when contrasted with his father's dramatic death. Sullivan just unceremoniously shoots him in the head while Connor's taking a bath.
- The Unfavorite: His father clearly prefers his surrogate son, Sullivan, over him. However, despite how much Connor disappoints him, his father still loves him to the point where he takes a hit out on his surrogate son to protect his biological son.
- "Well Done, Son!" Guy: Connor clearly wants his father's love and respect but his incompetence and instability only makes him a screw up who only gains his father's disappointment.
- Would Hit a Girl: Murders Annie Sullivan while trying to kill her son.
- Would Hurt a Child: When Michael Jr. watches him murder Finn McGovern, Connor tries to cover his tracks by killing the witness. Instead, he murders Peter by mistake.
The underboss for the Al Capone Outfit.
- Know When To Fold Them: As soon as Rooney's dead and protecting Connor is no longer profitable, Nitti tells Sullivan where Connor is hiding and calls off the hit on him and his son.
- Mouth of Sauron: Since Al Capone is never seen in the movie, Nitti serves as his representative.
- Would Hurt a Child: He tries to persuade Rooney to order a hit on Michael Jr. due to the threat the kid could pose in the future.
The wife of Michael Sullivan, Sr.
- Happily Married: She and Michael Sr. are a very loving couple.
- Senseless Sacrifice: To her credit, she tries to save Peter's life by shielding him with her body. Unfortunately, Connor kills them both anyway.
- We Hardly Knew Ye: Both she and Peter are killed thirty minutes into the movie without much characterization.
An accountant who holds the ledgers for the Rooney crime syndicate.