The Warner Siblings (also known as "the Animaniacs" by fans and the media) are small, silly, mischievous, anthropomorphic toon siblings of unknown origin and the central titular characters of the series; they generally introduce and identify themselves as "the Warner Brothers (and the Warner Sister)". Their species is never made clear: this has been satirized several times, most prominently in the song "What Are We?". While no writer or creator has confirmed the idea, Dot's name has implied that they may also be derived from "Warner Brothers" itself: Yakko's position as de facto leader can be symbolized as the prominence of "Warner", Wakko being the younger brother can be seen as the prominence of "Bros", and "Dot" may simply come from the period found at the end of the title of the company.
Yakko (voiced by Rob Paulsen) – Yakko is the wise-cracking, smart-and-fast-talking, oldest sibling—at 14 years old—who usually acts as the leader of the trio. He gets his name for his talkative nature being generalized as loquacious. As per his age and consequent obsession with girls, Yakko is responsible for most of the adult humor, saying "Goodnight, everybody!" after a joke that only adult viewers will understand. Yakko wears pants that are "smokey topaz" with a blackbelt. Animator Tom Ruegger's son Nathan is known for being the inspiration for Yakko.
Wakko (voiced by Jess Harnell) – Wakko is the middle sibling—at 11 years old—who has a huge appetite and magical "gag bag" full of tricks. They earn their name for being the most outrageous in physical comedy—and supposedly the least intelligent—though Wakko has claimed it to be "middle kid syndrome" in the episode "Survey Ladies". Wakko wears a candy apple red backwards baseball cap and a pale blue turtleneck sweater. Their "Great Wakkorotti" segments also see him belching professionally to classical music, where their belches were provided by Maurice LaMarche. While Wakko often gets disappointed with them-self, they have only shown to get really angry once, in "Chalkboard Bungle", after Miss Flamiel deliberately hurts their feelings. They get very riled up and breathe fire, while their siblings seem unperturbed by their actions, and the scene cuts away before they can unleash true destruction, leaving their full capabilities ambiguous. In the reboot, upon thinking someone had stolen their donuts, they say that they will "turn their faces into mashed potatoes with butter and gravy." They are the only sibling that doesn't speak with an American accent. Instead they speak with a Scouse/Liverpool dialect inspired by The Beatles.
Dot (voiced by Tress MacNeille, occasional singing voice provided by Missi Hale in reboot) – Dot is the cute and sassy youngest sibling—at 10 years old—who is more easily relaxed than her brothers, but proves on numerous occasions that she can be just as wild as they are. Her full name is Princess Angelina Contessa Louisa Francesca Banana Fanna Bo Besca III; she also despises being referred to as "Dottie", threatening anyone who does so with death. She is said to be both a tomboy and feminine. She wears a pink skirt with a yellow flower ribbon around her ears.
Dr. Otto von Scratchansniff – The WB studio psychiatrist, voiced by Rob Paulsen, who attempts to force the Warner siblings to be less zany. He often loses patience with the Warner kids and freaks out—his first chronological interaction with them sees him literally pulling out his hair until he achieved his characteristic baldness—but then becomes fonder of and takes more responsibility for them as the series progressed, occasionally acting as a father figure; the Warner siblings are clearly shown to be annoying him on purpose, but are also very fond of him. In the revival's season 1 finale's first sketch "Hindenburg Cola", Otto successfully pranks the Warner siblings in his return, believing that the revival will allow him victories every now and then, only to fall victim to the titular beverage as the karmic result of his prank, much to his horror.
Hello Nurse – A buxomblonde WB studio nurse who also appears in other occupations and is voiced by Tress MacNeille, over whom various males—particularly the Warner Bros, Yakko and Wakko—fawn. Her appearance usually prompts the Warner brothers into affectionate greeting of "Hellooooooo, nurse!" occasionally accompanied by leaping into her arms or big kisses, although sometimes any number of all three WB siblings use the same gag on other characters. Hello Nurse appears in a few Slappy cartoons as a running gag. In Animaniacs: Wakko's Wish, it is learned that her "mean IQ (is) 192" and she laments that she is respected for her looks and not her mind (except by Yakko and Wakko, ironically). The phrase "Hellooooooo, nurse!" was initially meant to be a catchphrase for Buster Bunny on Tiny Toon Adventures as a counterpart for Bugs Bunny's "Eh, what's up, Doc?", but the writers could not find an appropriate way for him to use the phrase organically; of course, the phrase did not originate there, having been used decades earlier in vaudeville shows. Creator Tom Ruegger shared on Twitter that the character's name is Heloise Nerz and she has German heritage. The era of the revival would deem Hello Nurse inappropriate, and so she is fully absent, with Dr. Scratchansniff providing the in-universe explanation of her joining Doctors Without Borders in the intervening two decades.
Ralph T. Guard – A dim-witted WB Studios security guard, voiced by Frank Welker, who is usually the one to recapture the Warner siblings and confine them to the Warner Bros. tower. He first appeared in Tiny Toon Adventures as the Fat Guard. Despite retaining his stupidity in the revival, he takes advantage of the Warner's lack of 21st century technology to contain them briefly. In the season 2 finale, he is revealed to be related to Nora Rita Norita and his real name is Ralphnazo.
Thaddeus Plotz – The squat, hot-tempered, money-grubbing CEO of Warner Bros., voiced by Frank Welker. His portrait is a prominent decoration of the CEO's office. He is not present in the reboot (except in the two-part "Wakkiver Twist"), as he has left his position at Warner Bros. sometime during the Warners' 22-year period of absence.
Nora Rita Norita – Plotz's successor in the revival, voiced by Stephanie Escajeda. Though as stern and short-tempered as Plotz, she takes the Warner Siblings' zaniness more passively; she is also obsessed with her health so as to maintain her slender frame, being seen on a treadmill in her first appearance and going into a frightening laughing fit when accused of eating stolen donuts in a later episode.
Nils Neidhart – An immensely muscular, narcissistic, and vindictive Liechtensteiner athlete with a massive ego, voiced by Fred Tatasciore, whom the Warners outsmart in the reboot. He prides himself on his muscles and laughs off those he assumes to be weaker than him. However, after the Warners outsmart him, he literally ends up trapped in Hell.
Pinky and the Brain are two anthropomorphic white mice kept in a cage at ACME Labs, voiced by Rob Paulsen and Maurice LaMarche, respectively. The Brain is serious and devious, the leader, and constantly devising plans to conquer the world. He resembles and sounds like Orson Welles. Pinky is eccentric and unintelligent but loyal to the Brain. In 1995, they were spun off into a cartoon series of their own. As of now, they are the only non-Warner Siblings segment to regularly appear in the 2020 revival series where Brain appears as more villainous. The revival revealed that the reason why Brain wants to take over the world is that he was frustrated and angered by how the scientists mistreated him when they demonstrated his helplessness during his youth, and since then, he vowed that he would be in control of what happens around him.
Billie – A anthropomorphic female white mouse, voiced by Tress MacNeille, who appeared in "The World Can Wait", "Brain Noir" and "You'll Never Eat Food Pellets In This Town Again!".
Julia (formerly J37 and then Julia Brain) – A female, tannish, genetically altered, anthropomorphic lab mouse and ex-wife of the Brain, voiced by Maria Bamford, who appears in the 2020 revival, first appearing in "Mousechurian Candidate". She was mutated by Brain using the DNA found on artifacts of past First Ladies of the United States to be his candidate for the position as he attempts to run for president. However, the public finds her more favorable and write her in instead, and Julia then defies Brain's schemes after finding them immoral. During a presidential debate in Nashua, New Hampshire, Brain attempts to control her using a neural implant in her left ear, but she overcomes his control through her own will. However, she cannot remove the malfunctioning device, continuously giving her electric shocks. She then flees, abandoning the debate and her candidacy. Although Pinky and the Brain assume that she has reverted to her primal, feral state, the end of the segment reveals that she is now planning to get her revenge. She returns in "Reichenbrain Falls", where she is revealed to have been driven mad by the electric shocks and has become malevolent, now wanting to take over the world for herself. She pretends to be Pinky and sets up a ruse to trick Brain into revealing the code to hack into the International Space Station and fire an electromagnetic pulse at Earth, tricking him into thinking that he's on the ISS when they're actually still at a school on Earth. The Brain sees through Julia's ruse, noticing that some of "Pinky's" mannerisms do not match up with the real one's, and he and the real Pinky fight back against her. Although she escapes them using a fully-functioning model rocket that Brain tricked some of the school's students into making, it explodes in mid-flight, and she instead rides a hawk vowing to return.
Snowball (voiced by Roddy McDowall) is an anthropomorphic lab hamster and Brain's former childhood friend-turned-rival who was also made intelligent by gene splicing and has a similar desire for world conquest (though his desire is far more malevolent than Brain's) which Pinky and Brain are sometimes forced to stop.
Larry (voiced by Billy West) is a anthropomorphic white mouse who was created as a response to demands from Kids' WB executives to include additional characters on the show. His presence is sporadic, as the writers of the show believed that including an additional character would ruin the chemistry between Pinky and Brain, as they worked best as a comedy duo; thus a third character would, therefore, be out of place and unnecessary to the plot. To further drive this point home, Larry's first appearance was marked by a modified version of the theme song with the words "and Larry!" shoehorned in between existing lyrics. He is a caricature of Larry Fine of The Three Stooges fame; therefore, the episode's title is "Pinky and the Brain...and Larry". He later makes a brief cameo in the Animaniacs revival series segment "The Flawed Couple", appearing in the title sequence of Narfs, a parody of Cheers.
Elmyra Duff (voiced by Cree Summer) is a redheaded girl. She wears a blue blouse, a white skirt, black Mary Janes over white socks, and a blue bow with a skull at the center. She originated as a character in Tiny Toon Adventures and appeared with Pinky and the Brain in a spin-off, Pinky, Elmyra & the Brain.
The Godpigeon (Chick Vennera) – A anthropomorphic pigeon who is an unintelligible parody of Marlon Brando's Don Vito Corleone in The Godfather. The bird's bulky appearance signifies Brando's massive weight gain, due to overeating habits in his later years. Bobby usually acts as interpreter for his gibberish.
Skippy Squirrel – Voiced by Nathan Ruegger, is an anthropomorphic squirrel and Slappy's grand-nephew, whose chipper personality is the opposite of his aunt's. His character varies from slightly naive ("Slappy Goes Walnuts") to innocent ("Bumbie's Mom") to complicit partner of Slappy ("Critical Condition").
Stephen Wolf - An anthropomorphicwolf and Walter's grandson, who appears in "...And Justice For Slappy". In the episode, he acted as Walter's attorney as part of Walter's plot to finally turn the table on Slappy as revenge for years of torment by her by putting her on trial for supposedly "assaulting him with a intent to squash" (even though he was the one who assaulted her first). However, Walter's plans eventually fail when Slappy is found innocent. As a result, he bruttally attacks his own grandson. Stephen is voiced by John McCann, who also wrote the episode in which Stephen Wolf debuted.
Sid the Squid – An anthropomorphicsquid and an villain similar to Chuck Jones' version of Daffy Duck, voiced by Jack Burns, who appeared in five Slappy cartoons: "Hurray for Slappy", "Scare Happy Slappy", "Rest in Pieces", "Macadamia Nut", and "Star Warners".
Beanie the Brain-Dead Bison – An anthropomorphicbison and an villain similar to Pete Puma, voiced by Avery Schreiber, who appeared in "Hurray for Slappy", "Scare Happy Slappy", "Rest in Pieces", "Macadamia Nut", and "Star Warners".
Duke – A school bully, voiced by Corey Burton in "Bully for Skippy".
Ms. Butley – Skippy's guidance counselor, voiced by Tress MacNeille in "Bully for Skippy".
Reef Blunt – A foe of Slappy and the chairman of the Federal Television Agency, who wanted everyone involved in children's television to follow the new strict guidelines, which includes decreasing amounts of cartoon violence and increasing education for three hours each day, much to the misery of Yakko and Slappy. He was voiced by Rob Paulsen in "Bully for Skippy".
Rita and Runt
These segments, along with "Minerva Mink", were discontinued at the end of Season 1 (in part, because of Bernadette Peters' salary). Welker remained a series regular, voicing other characters. Rita and Runt returned as minor characters toward the series' end. They also appear as minor characters in the feature-length direct to video Animaniacs animated film Animaniacs: Wakko's Wish.
Rita and Runt are a vagabond stray duo that get into many scraps and adventures. They are often searching for a home, but are back as strays by the end of the episode. In Animaniacs: Wakko's Wish, they are shown finally being accepted in a home, a result of Wakko's wish for two ha'pennies, which caused several characters to receive their heart's desires.
Runt (voiced by Welker) – Runt is a dim-witted dog who thinks that Rita is also a dog like himself and who constantly uses the word "definitely" when speaking (for example, "Rita, you're a good dog. Definitely a good dog!"). This verbal tic, as well as Runt's speaking style, is a reference to Dustin Hoffman's character in Rain Man. He also has a few anthropomorphic traits, even though these are rarely shown.
Dr. Phrankenstein – A stumpy female mad scientist, voiced by Adrienne Alexander in "Phranken-Runt"
Scout– Dr. Phrankenstein's creation, voiced by Frank Welker in "Phranken-Runt"
Mr. Squeak – Dr. Phrankenstein's pet rat in "Phranken-Runt"
Mrs. Mumphead – An eccentric old lady, voiced by Paul Rugg, in "No Place Like Homeless"
Crackers the Parrot – Mrs. Mumphead's pet parrot, voiced by Frank Welker in "No Place Like Homeless"
Kiki the Angry Ape – An ill-tempered gorilla, voiced by Frank Welker, who appears in "Kiki's Kitten"
Mr. Politician – A parody of Ross Perot, voiced by Frank Welker, who appears in "Icebreakers"
Missy "Ma" McCoy – An elderly farm cat, voiced by Tress MacNeille
Buttons and Mindy
Buttons is a German Shepherd Dog who watches Mindy when her parents are away. He also has some rarely shown anthropomorphic traits. His vocal effects are provided by Frank Welker. Mindy, voiced by Nancy Cartwright, is a young girl who constantly wanders into trouble without even being aware of it. Buttons haplessly struggles with various dangers and narrowly rescues Mindy, only to be blamed and punished for her misbehavior. There is no consistency or continuity in the storytelling; most episodes each feature Mindy's family living in a different setting and portraying them as different sorts of people (i.e. costumed superheroes, mer-people, cave people, etc.). In Animaniacs: Wakko's Wish, Buttons is rewarded with some good steak instead of being punished.
Mindy's mother – In brief off-camera appearances, her face is never shown and she is usually called "Lady" by Mindy in the series; in Animaniacs: Wakko's Wish, Mindy finally calls her "Mom". She has the same voices as Mrs. Martha Moppet (Lulu's Mom) from The Little Lulu Show on CINAR and Anita Radcliffe from 101 Dalmatians on Disney. She is voiced by Tress MacNeille.
Mindy's father – His face is also never shown; Mindy usually calls him "Mr. Man". He has the same voice as Roger Radcliffe from 101 Dalmatians on Disney. He is voiced by Frank Welker.
Katie Ka-Boom is a teenage girl voiced by Laura Mooney, who morphs into various violent, destructive monsters when things do not go her way. She lives with her parents and her little brother named Tinker. Katie is the only member of her family who has blonde hair while the rest of her family are brunettes. The premiere Katie Ka-Boom segment was also a Chicken Boo crossover, in which Katie morphs into a green Incredible Hulk-like monster when initially told her new boyfriend (who is also the student council president, class valedictorian and the school's star wrestler) is a giant chicken, and then morphs into a monster made of fire when she herself realizes that he is a giant chicken and ends their relationship. Writer Nicholas Hollander based Katie on his own daughter, who, at the time, was going through a similar tantrum phase.
In the reboot episode "Good Warner Hunting", Katie is seen with the previous cartoon characters and her appearance suggests that she is now an adult.
Tinker Ka-Boom – Katie's little brother, who is five years old and in kindergarten. He wears a blue shirt and red hat like Wakko. Tinker is voiced by Justin Garms.
Newt – The faithful anthropomorphic dachshund of his lazy owner, who also appears in "Puttin' on the Blitz" with Rita and Runt as "Schnappsie". Voiced by Arte Johnson (Newt) and by Frank Welker (Schnappsie).
Wilford B. Wolf – A anthropomorphic nerdy wolf who becomes a handsome werewolf every night of the full moon, voiced by Peter Scolari. His werewolf alter-ego is built like a Chippendales dancer and dresses like one, and he is very affectionate to Minerva. Minerva once asked him about his werewolf changes and when will the next full moon come, Wilford answers that it comes every 28 days, to which she implied "Good things are worth waiting for."
The Hip Hippos
Flavio and Marita, also more commonly known as the Hip Hippos, are a wealthy, Spanish, anthropomorphic hippo couple voiced by Frank Welker and Tress MacNeille (singing voices done by Wendy Knudsen for Marita and Ray McLeod for Flavio).
Dr. Gina Embryo – A human zoologist who studies the Hip Hippos and tries in vain to protect them, a parody of both Joan Embery and Jane Goodall, voiced by Tress MacNeille.
The Maid - The Hip Hippos' anthropomorphicgiraffemaid who appears in the debut Hip Hippos cartoon "La Behemoth", voiced by Tress MacNeille.
Other supporting characters
Mr. Director (voiced by Paul Rugg) – A recurring character that is a caricature of actor and director Jerry Lewis who always speaks in a whiney childish-like tone, he often shouts out nonsensical words like "Flamiel", or "Freunlaven" and also screams out "Lady!".
Miss Flamiel (voiced by Tress MacNeille) – The studio's strict teacher who Plotz hired as a way to control the Warner siblings' behavior (which obviously failed). Whenever someone does something wrong or incorrect in front of her, she gets out a red marker (black in Wakko's case) and writes "F" on their forehead, as shown in "Chalkboard Bungle". In other episodes, she is less strict, while the Warners are cooperative as shown in "Wakko's America" where she hosts a game of Jeopardy!, and Wakko, who lands the Daily Double, wagers all of his money to name all 50 states and capitals. Wakko does so, but fails because he answers in the form of a song and not a question.
The Little Blue Bird ("Birdie") – A young blue bird with many few anthropomorphic traits, voiced by Cody Ruegger. He debuts in the one-shot cartoon "Wild Blue Yonder", believing a stealth bomber to be his mother.
Chicken Boo – A six-foot-tall chicken, voiced by Frank Welker. He wishes to live as a human, so he wears flimsy disguises, usually just a hat or a coat, which somehow always fool everyone – except for one person whom no one believes. Unlike other animal characters, Boo cannot talk and acts almost exactly like a real chicken, making his disguises all the more absurd. However, he does have various anthropomorphic traits. At the end of each episode, his disguise falls apart, and he is exposed as a giant chicken. This causes all of his previous supporters to turn against him (after the person who was originally not believed says "I told you that guy was a chicken!") and usually run him out of town. In the revival, it's revealed that in the years since the original show's end, he has greatly improved his disguising ability to the point that he can legitimately appear as a human, even being able to speak English when disguised. However, he was apparently not supposed to appear in the revival as he was, according to the Warners, the least popular character in the show (with Yakko screaming, "Bottom of every fan list!", even though the Warners were wondering where he went along with the rest of the original cast). Boo disguised himself as a hunter named Dr. Walter Grubb and hunted down the original Animaniacs cast (except for Pinky and the Brain, Thaddeus Plotz, Hello Nurse, Ralph the Guard and Dr. Scratchansniff) in revenge and supposedly killed them and tried to hunt the Warners as well until they tricked him into removing his disguise and exposing his identity, and the rest of the original Animaniacs cast were later revealed to all be alive, freed by the Warners, and run Boo out of the Warner Bros. lot.
Steven Spielberg (voiced by Frank Welker in the original, Andy Milder in the revival) – The show's executive producer, often mentioned by the cast, although he has made a small amount of physical appearances. These include an appearance as "His Eminence" in "Hooked on a Ceiling."
Colin (the Randy Beaman Kid) – A wide-eyed boy who tells improbable stories which allegedly happened to his (never-seen) friend Randy Beaman. He comes out of his home with an object in hand that he fidgets with while he tells the story (the object is usually not related to the story) and starts off with "One time...okay, see, one time..." and then tells his story while playing with whatever he has. When he is finished, something will usually happen to the object that he is playing with (like an ice cream cone melting or a baseball going through someone's window), and the kid will finish with "'kay, bye.", then turn around and walk back into his house without another word. He's voiced by Colin Wells, son of Deanna Oliver.
The Flame – A talking childlike candle flame, voiced by Luke Ruegger, who is present at important historical events and teaches fire safety.
Charlton "Baynarts" Woodchuck – A anthropomorphicwoodchuck and cartoon director and former child actor who first appears in "Hollywoodchuck" and later returns as the star of "The Kid in the Lid" and also appears in a My Father, the Tuna gag in "The Warners' 65th Anniversary Special" and as a guest character in the Slappy Squirrel cartoon "Nutcracker Slappy", voiced by Jeff Bennett. The segment "Hollywoodchuck" revealed that he hails from Kansas.
The Mime – A nameless and accident-prone mime who appears in "Mime Time", also narrated by Bodett.
Mary Hartless – A parody of Mary Hart, voiced by Valri Bromfield and Tress MacNeille, who appears as a newsreader with a variety of hairstyles in "Hurray for Slappy", "Chairman of the Bored", "Bubba Bo Bob Brain", and "Critical Condition".
Death – A reaper with a black robe, skeletal appearance and scythe. In "Meatballs or Consequences" the Warner siblings challenge him to a game of checkers, reminiscent of the chess game with Death in Ingmar Bergman's 1956 The Seventh Seal.
The Narrator – The offscreen narrator (voiced by Jim Cummings) whose voice resembles Cummings' voice for WD’s Winnie the Pooh, who appears in "Nighty-Night Toon", "Gift of Gold", and "Warners and the Beanstalk". A variant of this narrator, voiced by Tom Bodett, appears during the "Good Idea-Bad Idea" and "Mime Time" segments.
Francis "Pip" Pumphandle (voiced by Ben Stein) – A man who tells long and boring stories and bores the Warners in "Chairman of the Bored". He also appears in the Pinky and the Brain episode "Star Warners", and returns in Animaniacs; Wakko's Wish as a Desire Fulfillment Facilitator.
Bugs Bunny (voiced by Greg Burson in the original) – An anthropomorphic wisecracking, carrot-loving rabbit and one of the biggest cartoon stars at the Warner Bros. studio.
Daffy Duck (voiced by Greg Burson in the original, Eric Bauza in the revival) – An anthropomorphic greedy, self-centered duck and one of the biggest cartoon stars at the Warner Bros. studio.
Starbox and Cindy (voiced by Danny Jacobs and Eleanor Johnson, respectively) – Starbox is a miniature alien whose job is to press a button to signal a hostile takeover of Earth. Unfortunately, he is captured by a kind-hearted girl named Cindy who plays with him and talks of nonsensical and slightly surreal things; as a result, the invasion is put on indefinite hold. The voice acting suggests that most of Cindy's dialogue is taken from Johnson's legitimate conversations with animation placed over it.
The Incredible Gnome in People's Mouths (voiced by John DiMaggio) – Once a narcissistic CEO, he has been transformed into a rage-driven gnome who goes inside people's mouths and tells others what they really think; comically popping out to scream. Once his job is done, he walks off into the sunset, a lá The Incredible Hulk.
Freakazoid (voiced by Paul Rugg) – An insane teenage superhero and the titular protagonist of the show of the same name. He cameos in "This Pun for Hire" and "The Big Wrap Party Tonight". He was originally set to appear in a segment from the 2020 revival, but this fell through due to actor availability.
The Munch-Man (voiced by Shah Rukh Khan) - A man who loves to eat everything in The World.