* "Diamond Joe" Quimby (Dan Castellaneta), "Bart Gets an F", corrupt mayor
o Martha Quimby (Maggie Roswell), mayor's wife
o Freddy Quimby (Dan Castellaneta), "The Boy Who Knew Too Much", mayor's nephew, troublemaking playboy
* Lou (Hank Azaria), "There's No Disgrace Like Home", police sergeant
* Eddie (Harry Shearer), "There's No Disgrace Like Home", police officer
* Rex Banner (Dave Thomas), "Homer vs. the Eighteenth Amendment", briefly replaced Clancy Wiggum as police chief, presumed deceased
* The Warden (Charles Napier), "Pokey Mom", Prison warden
* Ray Patterson (Steve Martin), "Trash of the Titans", (former) sanitation commissioner (refused to rejoin the sanitation department after the people Springfield asked him to replace Homer (who beat him in the election)
* Mary Bailey (Maggie Roswell, Tress MacNeille), "Two Cars in Every Garage and Three Eyes on Every Fish", state governor
* Robert "Bob" Arnold (Hank Azaria), "Mr. Lisa Goes to Washington", former Congressman, expelled for bribery and corruption
* Judge Roy Snyder (Harry Shearer), "Krusty Gets Busted", veteran judge
* Judge Constance Harm (Jane Kaczmarek), "The Parent Rap", newer judge
* Russell "Russ" Cargill (Albert Brooks), "The Simpsons Movie", head of the Environmental Protection Agency and main antagonist of the film
* Snake Jailbird (Hank Azaria), "The War of the Simpsons", criminal
o Jeremy Jailbird, Snake's son
o Gloria (Julia Louis-Dreyfus), Snake's girlfriend
o Shoshanna "Bart Sells His Soul", Snake's girlfriend
* Robert "Sideshow Bob" Underdunk Terwilliger (Kelsey Grammer), "The Telltale Head", attempted murderer
o Francesca Terwilliger (Maria Grazia Cucinotta), "The Italian Bob", Sideshow Bob's wife
o Gino Terwilliger, "The Italian Bob", Sideshow Bob's son
o Dr. Robert Terwilliger, Sr. (John Mahoney), "Funeral for a Fiend", Sideshow Bob's father
o Dame Judith Underdunk (Tress MacNeille), "Funeral for a Fiend", Sideshow Bob's mother
o Cecil Terwilliger (David Hyde Pierce), "Brother from Another Series", Sideshow Bob's brother
* Lucille Botzkowski or Ms. Botz (Penny Marshall), "Some Enchanted Evening", Babysitter Bandit
* Molloy (Sam Neill), "Homer the Vigilante", the "Springfield Cat Burglar"
* Hank Scorpio (Albert Brooks), "You Only Move Twice", charismatic supervillain and owner of Globex Corporation
* Lyle Lanley (Phil Hartman), "Marge vs. the Monorail", conman
* César and Ugolin (Harry Shearer and Dan Castellaneta), "The Crepes of Wrath", French winemakers
* Don Vittorio Di Maggio or Don Vittorio Dimaggio (they are both two Italians surnames) (Hank Azaria), "Homie the Clown", godfather
* Marion Anthony "Fat Tony" D'Amico (Joe Mantegna), "Bart the Murderer", mob boss
* Joey (Phil Hartman), "Bart the Murderer", mob henchman
* Legs (Hank Azaria), "Bart the Murderer", mob henchman
* Louie (Dan Castellaneta), "Bart the Murderer", mob henchman
* Johnny Tightlips (Hank Azaria), "Insane Clown Poppy", mob henchman
* Frankie the Squealer (Dan Castellaneta), "Insane Clown Poppy", mob henchman/informant
* Comic Book Guy né Jeff Albertson (Hank Azaria), "Three Men and a Comic Book", owner of the Android's Dungeon Comics & Baseball Card Shop
* Rich Texan (Dan Castellaneta), "$pringfield", stereotypical rich, callous business owner.
* Herman (Harry Shearer), "Bart the General", one-armed veteran, owner of Herman's Military Antiques
* Jack Larson, president of Laramie Cigarettes
* Akira (George Takei, Hank Azaria), "One Fish, Two Fish, Blowfish, Blue Fish", restaurateur and part-time martial-art teacher
* Luigi Risotto (Hank Azaria), Italian American restaurateur
* Captain Horatio McCallister or the Sea Captain (Hank Azaria), "New Kid on the Block", restaurateur and charter boat operator
* Howard K. Duff VIII (Stacy Keach), "Hungry, Hungry Homer", owner of Duff Beer and the Springfield Isotopes
* John (John Waters), "Homer's Phobia", owner of antiques and collectibles store in the Springfield Mall.
* Ms. Sinclair (Jon Lovitz), A Streetcar Named Marge, owner of the Ayn Rand School for Tots nursery
* Goose Gladwell, "Fat Man and Little Boy", eccentric Willy Wonkaesque clothing and novelty store entrepreneur
* Frank Ormand (Jack Lemmon), "The Twisted World of Marge Simpson", pretzel franchise owner, deceased
* Jake (Dan Castellaneta), "The Tracey Ullman Show shorts", barber, owner of Jake's Unisex Hair Palace
* Cowboy Bob (Albert Brooks, Dan Castellaneta), "Call of the Simpsons", owner of Bob's RV Round-Up
* Belle (Tress MacNeille), "Bart After Dark", burlesque house madam
* Mr. Costington (Dan Castellaneta), "Trash of the Titans", Costington owner
* Lionel Hutz (Phil Hartman), "Bart Gets Hit by a Car", lawyer and real estate agent (character retired due to death of Phil Hartman)
* Gil Gunderson (Dan Castellaneta), "Realty Bites", incompetent lawyer and salesman
* Squeaky Voiced Teen né Jeremy Peterson/Freedman (Dan Castellaneta), "Brush with Greatness", fills various positions at entry-level part-time jobs around Springfield, son of Lunchlady Doris.
* Professor John Frink (Hank Azaria), "Old Money", scientist, inventor, entrepreneur, and former lecturer at the University of Springfield.
o John Frink, Sr. (Jerry Lewis), "Treehouse of Horror XIV", swashbuckling scientist, zombie and serial murderer (non-canon).
* Hans Moleman (Dan Castellaneta), "Principal Charming", elderly recurring character.
* Don Brodka (Lawrence Tierney), "Marge Be Not Proud", Try & Save security guard
* Duffman alias Barry Duffman alias Sid alias Larry (Hank Azaria), "The City of New York vs. Homer Simpson", product promoter. It is implyed that each alias is in fact a different person who portrayed Duffman.
* Lindsey Naegle (Tress MacNeille), "The Itchy & Scratchy & Poochie Show", entrepreneur and executive.
* Cookie Kwan (Tress MacNeille), "Realty Bites", successful realtor
* Dave Shutton (Harry Shearer), "Two Cars in Every Garage and Three Eyes on Every Fish", Springfield Shopper reporter.
* The Yes Guy (Dan Castellaneta), "Mayored to the Mob", restaurateur, waiter, salesclerk, and election-day poll worker.
* Wiseguy (Hank Azaria), "The Way We Was", holder of numerous jobs around Springfield. Identified as "Raphael" by Sideshow Bob in "Day of the Jackanapes".
* Hollis Hurlbut (Donald Sutherland), "Lisa the Iconoclast", curator of the Springfield Historical Society