- Don Vittorio DiMaggio - Commands the respect of the mob and even Fat Tony defers to him.
- Michael D'Amico - Fat Tony's son
- Frankie the Squealer - Soldier
- Jimmy the Snitch
- Unnamed Consigliere - Consigliere
- Lefty - Caporegime
- Righty - Caporegime
- Joe The Rogue - Soldier
- The Hat - Soldier
- Jimmy - Soldier/Hitman
- Joey (mafia) - Soldier
- Joey the Arsonist
- Dan Gillick - Accountant
- Snake Jailbird - Seen on chart
- Kenny "The Problem"
- Jimmy "The Axe"
- Tommy the Face-shooter
- Ronnie "The Rifle"
- Shotgun Mike
- Shotgun Pete
- Shotgun "The Rifle"
- Marion Anthony "Fat Tony" D'Amico (deceased) - boss
- Homer Simpson - Briefly Fat Tony's consigliere
- Bart Simpson (temporary)
- Nicky Bluepants Altosaxophony (undercover informant, actually Homer Simpson)
- Dante Calabresi (murder) - Dissident caporegime
- Dante Calabresi jr. (murder) - Dissident soldier
- Primo (murder) - Dissident soldier
- Johnny "Two Times" (temporary) - Soldier
- Jimbo (recuit by Michael D'Amico)
- Dolph (recuit by Michael D'Amico)
- Kearney (recuit by Michael D'Amico)
- The Springfield mafia conducts its business and socializes in the Legitimate Businessman's Social Club.
- Gambling is one of the mob's ventures.
- The mafia has strong control over illegal fireworks sales and rats milk production.
- The mob helped out Marge Simpson's pretzel business by attacking her competitors.
- The mafia is also responsible for tobacco, drug, and alcohol trafficking. When Springfield reenacts Prohibition, he pays off police officers to smuggle the booze into the town.
- The mob offers protection to Krusty Burger from competitor restaurants such as McDonalds and Burger King.
- The mafia also built a wheelchair navigation ramp system for Springfield Elementary School which ended up collapsing, due to having been made out of breadsticks, before it could see official use (It was originally developed to help Bart get around the school when he was confined to a wheelchair, but that fell through after he made an unexpectedly quick recovery), which also forced Springfield Elementary to close permanently.
- They were gluing cotton balls on ferrets and selling them to pet shops, as toy poodles, in Poppa's Got a Brand New Badge -- until they were arrested by SpringShield due to one of their products being attached to a wire.
- The mafia distributed milk for the various schools under the name Squeaky Farms Brand Genuine Animal Milk, which as the name implied used rats as the ingredient instead of cows or even at a minimum dogs (which was what Quimby had been promised), as Homer, at the time acting as one of Mayor Quimby's bodyguards, discovered this, and pressured Quimby to shut it down.
- Although technically not a real business dealing, the mafia when disposing of a cadaver in a dumpster that was otherwise reserved for discarded Christmas toys once covered their actions to Chief Wiggum by claiming that they were getting rid of a "beanie baby."
The mafia often punishes people for things that are either an insult to them or if they don't pay back their debts. For instance, when Homer ended up borrowing money from Fat Tony and losing it in a football game, Fat Tony "hammered down" a payment plan by having Louie hammer Homer's hand (using two hammers if he mentioned Professor Pigskin). They also collectively hammered both Homer's hands when the latter asked them if they were the gay mafia.
Springfield Mafia Families
- The Calabresi crime family (poisoned)
- The Springfield mafia crime syndicate.
- Castellaneta crime family. (defunct)
Although not actually stationed in Springfield, the Cuomo, Travolta, Lasorda, and Boyardee Mafia families had ties to the Springfield mafia crime syndicate, and had once participated in a mafia summit (which ended up ruined due to Krusty the Clown and Homer Simpson unintentionally instigating a shootout from dropping various violin containers containing tommy guns while trying to retrieve the former's daughter's violin).
- It originally parodied the Corleone crime family from The Godfather series, and later Goodfellas and The Sopranos.
- Fat Tony's mafia has been seen in jail more than once, but usually escape easily.
- Episode – "Bart the Murderer"
- Episode – "Homie the Clown"
- Episode – "Mayored to the Mob"
- Episode – "Poppa's Got a Brand New Badge"
- Episode – "The Mook, the Chef, the Wife and Her Homer"
- Episode – "Donnie Fatso"
- Episode – "The Real Housewives of Fat Tony"
- Episode – "22 For 30"
- – The Simpsons Movie
- Video game – The Simpsons: Hit and Run
- Video game – The Simpsons: Tapped Out