!Main Characters
-> Voiced by: Creator/JimCummings
* AbhorrentAdmirer: Occasionally portrayed as this towards Shriek.
* ButtMonkey: Attracts a lot of pain, sometimes due to Dog's carelessness.
* {{Catchphrase}}:
** "Bee-yoo-tee-ful!"
** "It just doesn't get any better than this!"
** "Terr-riffic" (sarcastically)
** A deep-voiced "Ohhh MOMMA" when he's feeling greedy.
* CatsAreMean: Sometimes. On occasion, he's downright cruel.
* CatsAreSnarkers: And how! [[spoiler: He gets it from his dad.]]
* TheChewToy: Poor guy can't seem to catch a break.
* ADogNamedDog: Just like Dog, he's a Cat named Cat.
* {{Greed}}: His obsession with money and material possession can go a little too far sometimes.
* HappilyAdopted: [[spoiler:The big movie about finding their long lost parents, they find out in the end that the parents that raised them as kids had adopted them. And were also a talking frog and a sasquatch. They never find out who their biological parents are, but are content to reunite with the ones that cared for them.]]
* JerkWithAHeartOfGold: He can be mean at times, but he does care about his brother.
* LaserGuidedKarma: Episodes where he acts selfish often end with him getting his comeuppance. For instance, "Fred the Flying Fish" has him lose the money he got from selling Fred to Rancid Rabbit with no regard for how Fred would be treated.
* LikeFatherLikeSon: His [[spoiler:adoptive]] father is also a snarker.
* MrViceGuy: He can be greedy, and cross the line into villainy, but most of the time he is the hero.
* NeatFreak: In contrast to [[ThePigPen Dog]].
* NoRespectGuy: He isn't very well liked in his town.
* SmallNameBigEgo: Cat quite often has an inflated opinion of himself.
* SurroundedByIdiots: He's even attached to one!
* ThisLoserIsYou
* TrademarkFavoriteFood: White fish chub. And fish in general. Perhaps best illustrated when he and Dog go to Rancid's all you can eat buffet and Cat expresses irritation at Dog's CrazyConsumption...until Rancid brings out a tray of sushi and Cat proceeds to go ''ballistic''.
-->'''Cat:''' Fishy...fishy...FISH!!!!! (''scarfs down as much sushi as he can'')
* WhyDidItHaveToBeSnakes: He has aquaphobia which makes him afraid of water. This is best shown when he's at the beach and the others challenge him to ride a big wave, in which he claims he only likes the big waves that are at least thirty feet high.

[[folder: Dog]]
-> Voiced by: Creator/TomKenny
* {{Adorkable}}: Has shades of it. [[spoiler:So does his mother.]]
* BerserkButton: Let's just say that stealing his bones from his bone cellar is a suicidal idea and leave it at that.
* BewareTheNiceOnes: Cat once learned the hard way not to ''actually'' make Dog angry.
* BigEater: His appetite appears to be limitless.
* BreakTheCutie: Dog is much more sympathetic than most people realize. He's been laughed at by the entire town of Nearberg for being a failure hero (Dog The Mighty), worked to the point of hypothermia in a sled dog race (Mush Dog Mush), almost sold off as a freak show attraction by his own brother after contacting a disease (Dog's Strange Condition), bullied by mailmen while in a depressed state (Fistful Of Mail), driven to the brink of paranoia (Safety Dog), spent an entire episode thinking he was allergic to his own brother (Sneezy Dog) and has been cheated and lied to several times by his own brother. He also came dangerously close to crossing the DespairEventHorizon in the Great Parents Mystery special.
* {{Catchphrase}}: "Hi-ho diggedy!!" Dog even ''calls'' it his catchphrase! [[spoiler: He gets it from his mom.]]
* {{Cloudcuckoolander}}: He is easily distracted by balls, garbage trucks, bones, food, and his overactive imagination.
* TheCuckoolanderWasRight:
** In "The Great Parent Mystery", Dog comes up with a lot of ridiculous theories about what happened to his and Cat's parents, such as being frozen in a block of ice at the North Pole, being abducted by aliens, and being enslaved by evil mutant tree gnomes. Their [[spoiler: adoptive]] parents later reveal that at least some of Dog's theories happened to them while they were looking for [=CatDog=].
** In "Meat Dog's Friends", Dog believes that meat comes from meat trees planted by Johnny Meatseed. After going insane from learning that meat is made from animals and attempting to eat his brother Cat when he can't go through with eating vegetables and rocks instead, it turns out that meat trees and Johnny Meatseed actually exist.
* TheCutie: So very much. It often goes hand in hand with his goofiness.
* TheDitz: Is often brainless, needing Cat to do everything for him.
* ADogNamedDog: Literally.
* DogsAreDumb: In fact, a good portion of the dogs on the show are portrayed this way.
* DumbBlond: Dog doesn't normally have hair however a flashback to TheSeventies has him with blond hair.
* DumbIsGood: Usually is the more reasonable one if Cat is being a major {{Jerkass}} in the episode.
* TheFool: Dog frequently causes multiple catastrophes and AmusingInjuries though more often than not fate is on his side and leaves him unscathed (and then punishes Cat twice as hard for the both of them).
* GeniusDitz: He's actually shown to be quite the SupremeChef in the Ingrid Twins' debut episode.
* HappilyAdopted: [[spoiler:The big movie about finding their long lost parents, they find out in the end that the parents that raised them as kids had adopted them. And were also a talking frog and a sasquatch. They never find out who their biological parents are, but are content to reunite with the ones that cared for them.]]
* IdiotHoudini: Dog is a hyperactive dimwit that causes chaos with his canine tendencies. It is usually Cat that suffers the consequences for it however.
* JerkassBall: Sometimes acts more insensitive than usual.
* {{Keet}}
* LethallyStupid: Has caused a lot of destruction just because he didn't know any better.
* LikeFatherLikeSon: [[spoiler: Like Mother Like Son]]
* ManChild: Very immature... not that he ''shouldn't'' be, considering he's a ''dog'', but combined with his ability to speak he qualifies as this trope.
* TheMillstone: Dog is usually the one who gets the pair into trouble.
* ThePigPen: Almost never cleans up after himself.
* PingPongNaivete: Somehow Dog is smart enough to know the ethics against cheating and doing schoolwork but not to realize that dragging his conjoined twin across the street may cause slight physical harm.
* TooDumbToLive: Some of the things he does could have gotten them killed.
* TrademarkFavoriteFood: Bones, moldy meat, and garbage.

!Supporting Characters
[[folder: Winslow]]
-> Voiced by: Creator/CarlosAlazraqui
* CatchPhrase: "What are you, nuts!?"
* CharacterizationMarchesOn: In the first episode, Winslow was less of a malicious prankster and more of an annoying [[TheGadfly gadfly]]. He was a little nicer to [=CatDog=] too, to the point that Cat actually seemed to like him.
* DeadpanSnarker: Part of his rude behavior toward [=CatDog=] is to make remarks at their expense.
* DropInCharacter: He lives in [=CatDog=]'s house (the finale implies that he was its original owner) but has his own place inside the walls of said house. His arrival on the scene usually involves him emerging from a small hole in the wall and saying "Hey there, [=CatDog=]!"
* EvenEvilHasStandards: Not quite evil, but in "Dog Power" he's genuinely appalled at Cat's treatment of Dog.
* EvilLaugh: His signature cackle.
* InformedSpecies: He's allegedly a mouse, but looks more like a [[Franchise/TheSmurfs Smurf]].
* {{Jerkass}}: The majority of the time, he is an unbearable asshole, mostly to Cat.
* JerkWithAHeartOfGold: Deep down, he cares about [=CatDog=]. In "All You Need Is Lube", he even schemes to help [=CatDog=] escape from [[IOweYouMyLife an overly grateful Lube's]] asphyxiating grip, and in "[=CatDog=] Doesn't Live Here Anymore", he starts mourning over [=CatDog=]'s absence after a while.
* JerkWithAHeartOfJerk: But, as seen in his final scene of the GrandFinale, not ''that'' much.
* LaserGuidedKarma: On occasion, he gets his just deserts for being a prick to [=CatDog=], like when they agree to wrestle him for making fun of their predicament in "Brothers' Day" or when they chase him for ditching them during their battle with the Greasers in "Siege on Fort [=CatDog=]".
* TheNapoleon: He's extremely small and not a very pleasant person.
* SitcomArchNemesis: To Cat.
* SmallAnnoyingCreature: Invoked. He considers himself a "harasser".

[[folder: Mervis and Dunglap]]
-> Voiced by: John Kassir
* DarkHorseVictory: [[spoiler: When [=CatDog=] races Mindy to the top of an unnamed mountain, Dunglap somehow made it up first since Cat forgot his earmuffs.]]
* MessyPig: Mervis, for a given definition of "messy".
* {{Nerd}}s
* OnlySaneMan: They are the only normal characters in the series.
* ThoseTwoGuys: They don't seem to serve any other purpose than this.
* VitriolicBestBuds: Often seen bickering and yet are always together.
* WickedWeasel: Averted with Dunglap, who is one of the nicest characters on the show.

[[folder: Mr. Sunshine]]
-> Voiced by: Creator/BillyWest
* BystanderSyndrome: He'd probably be the OnlySaneMan if he didn't succumb to this all the time.
* CartoonCreature: Nobody's quite sure ''what'' he is. WordOfGod says he was originally supposed to be a monkey.
* DeadpanSnarker: Sometimes.
* TheEeyore: Subverted; he isn't so much depressed as he is boring and deadpan.
* IronicName: He's anything but sunny. Zig-zagged in that "The Ballad of Ol' 159" reveals that he used to be as cheerful as his name suggested.
* LazyBum: He often falls asleep while doing his job.
* TheLoad
* PerpetualFrowner: He never smiles.
* TheStoic: Always speaks in a dull monotone voice.

[[folder: Lola Caricola]]
-> Voiced by: Creator/NikaFutterman (credited as "Nika Frost" until "The Great Parent Mystery")
* ActionGirl: She gained her love of zoology after helping her family wrangle cattle. Not to mention the fact that she can go toe to toe with ''the Greasers''.
* ArtisticLicenseOrnithology: She looks and acts nothing like the type of bird she's supposed to be.
* CatchPhrase: "Unbelievable!"
* ChuckCunninghamSyndrome: She doesn't appear in any of the episodes after "The Great Parent Mystery"
* ForScience: Most everything she does. Justified because she's a zoologist.
* GenkiGirl: She's very perky.
* InformedSpecies: She's apparently a whip-poor-will. Specifically, she says that she's a "yellow-bellied whip-poor-will", a species that doesn't even ''exist'' in real life.
* TheLadette
* NiceHat: She wears a big hat with a feather in it, though she sometimes goes bareheaded.
* NotSoAboveItAll: She's always willing to join in with [=CatDog's=] shenanigans.
* OnlySaneWoman: To some degree.
* SmallAnnoyingCreature: Over-the-top, loud, repetitive, especially with catch phrase.
* PhraseCatcher: [[RhymesOnADime "Hola Lola]]", usually said by Cat.
* PunnyName
* ShipTease: Occasionally seems to flirt with [=CatDog=], although that was mostly in her first appearance.
* SlapstickKnowsNoGender: She's not immune to the AmusingInjuries everyone else on the show gets.
* TheSmartGirl: She's very intelligent.
* StrongFamilyResemblance: Her mother looks like an overweight version of her. It is shown in "The Great Parent Mystery" that her father also resembles her a bit.
* SpicyLatina: TheLadette, if she were of Latino descent.
* TheThingThatWouldNotLeave: In her first appearance "Sweet and Lola", where she decides to study [=CatDog=] and in doing so keeps invading their privacy and never leaving them alone. Subverted in that she eventually tells them indignantly that she would have left if they asked her to.

[[folder: Randolph Grant]]
-> Voiced by: Creator/BillyWest
* AmbiguouslyGay: Overall the mannerisms of this celeb and posh stylish character show hints of being gay and at times he seems to have a thing for Dog, especially in episodes "[=CatDog=]'s End", "Dog the Not so Mighty", and "Dog Ate It".
* CatchPhrase: "And I LOVE it!"
* NoCelebritiesWereHarmed: He's a dead ringer for Cary Grant.
* UpperClassTwit: Granted, he's a relatively amicable one.

[[folder: The Ingrid Twins]]
-> Voiced by: Laraine Newman
* AlwaysIdenticalTwins: They look alike and even have the same name.
* OppositesAttract: In one episode, it's shown that the GenkiGirl Ingrid likes DeadpanSnarker Cat and the DeadpanSnarker Ingrid likes [[{{Keet}} Genki Guy]] Dog.
* SexyScandinavian: Both are beautiful blondes and presumably Swedish, sharing a stereotypical Scandinavian name.
* ShipTease: They often appear on dates with [=CatDog=].
* SiblingYinYang: One of them is a GenkiGirl and the other is a DeadpanSnarker, hence why they're pretty much perfect for our conjoined duo.

[[folder: The Greasers]]
-> Voiced by: Creator/TomKenny (Cliff), Maria Bamford (Shriek), Creator/CarlosAlazraqui (Lube)
* BolivianArmyEnding: They're last seen [[spoiler: getting eaten by a giant sea monster. The reason it's this and not [[KilledOffForReal a certain other trope]] is because Cat, Dog and their parents all survived the same fate, so it's possible that the Greasers would get out too ([[GrandFinale not that it really matters]]).]]
* CoDragons: They sometimes help out Rancid Rabbit, when he's the main antagonist of the episode.
* DumbIsGood: Zigzagged; although he's still an active part of the gang in their mayhem and bullying, Lube is both the dumbest member and the nicest.
* EmbarrassingFirstName: Cliff's name is short for Clifford, which he isn't proud of -- although he thinks it's better than his EmbarrassingMiddleName of "Maurice". Shortly after, it's revealed that Lube's name is Ignatius, though he doesn't mind.
* FantasticRacism: They really hate cats. Crosses over with AnimalJingoism because they're dogs.
* FatBastard: Cliff is the chubbiest and the meanest.
* GangOfBullies: The group of three make up a team of delinquents.
* GeniusDitz: Lube is incredibly stupid most of the time, but he's also revealed to be a skilled mechanic.
* HiddenDepths: All three of them have these. Cliff is very much [[RealMenWearPink in touch with his feminine side]], Shriek has a crush on Dog and is SecretlyWealthy and Lube is a skilled mechanic.
* {{Jerkass}}: A trio of bullies who always pick on [=CatDog=].
* LikeParentLikeChild: Lube's parents are shown in the finale, and they're just as dumb as he is.
* MeaningfulName: Shriek. She shrieks. Boy does she ''[[CuteButCacophonic shriek]]''.
* NiceMeanAndInBetween: Lube is the TokenGoodTeammate and too dumb to know any better, Cliff is an unforgiving bully, and Shriek does have a softer side, but is normally malicious.
* QuirkyMiniBossSquad: When Rancid is the BigBad, they're usually acting as his minions.
* RealMenWearPink: Cliff [[spoiler: takes ballet]]. He's not only really good at it, but he's also really ''proud'' of it.
* SecretlyWealthy: Shriek. [[RebelliousPrincess She really hates it, though.]]
* SlapstickKnowsNoGender: Whenever Lube and Cliff get [[AmusingInjuries injured amusingly]], Shriek isn't spared just because she's a girl.
* SpoiledBrat: Shriek is a wealthy rebel.
* StrongFamilyResemblance:
** Shriek and her parents are shown to look a lot alike in "Rich Shriek, Poor Shriek".
** In "Back to School", [=CatDog=] encounters Cliff's nephew Biff, Shriek's nephew Squeak, and Lube's nephew Bartholomew, who all look like their uncles and aunt. In a flashback, we also see Cliff's dad, who looks just like his son.
** It is shown in "The Great Parent Mystery" that Cliff's mom also looks like her son and that Lube bears some resemblance to his parents as well.
* TerribleTrio: These three are always looking for trouble.
* TokenGoodTeammate: Lube is not only the nicest Greaser, [[UpToEleven he's probably the nicest character in]] ''the entire show''.
* TrueCompanions: [[DependingOnTheWriter Several episodes]] show them to be this. They may be rather nasty bullies, but they stick together.
* UnmanlySecret: Cliff has several that he reveals in one episode, including an EmbarrassingMiddleName and the fact he still wets the bed. Ironically, the one secret of his that Cat and Dog ''think'' is this trope turns out to be something he's actually [[RealMenWearPink really proud of]].
* VillainousCrush: Shriek has a crush on Dog. Strangely enough, ''Cat'' seems to be attracted to her. A few episodes suggest that Dog reciprocates Shriek's crush. In one where they're all convinced that the apocalypse is coming, Shriek confesses to and kisses him, prompting Dog to go into PostKissCatatonia with a big goofy grin on his face.
* YouAreWhatYouHate: [[spoiler:The GrandFinale reveals that Lube is part-cat.]]

[[folder: Rancid Rabbit]]
-> Voiced by: Creator/BillyWest
* BigBad: Nearly every episode he's in has him as the main antagonist.
* BigBadWannabe: Deteriorates into this as the show went on.
* CatchPhrase: "Leaping lumbago!" and "What what WHAT!?"
* CorruptCorporateExecutive: It's implied that he actually ''owns Nearburg''.
* TheDitz: Sometimes.
* EvenEvilHasStandards: Seeing [=CatDog=] swarmed with psychotic fleas and the flea belt no longer being enough to help them is enough to convince him to give them a flea bath with no apparent ulterior motive.
* FatBastard: Not as chubby as Cliff, but still counts.
* {{Jerkass}}: He's very antagonistic towards [=CatDog=]. In one episode, he bans them from a taco restaurant for no reason.
* MayorPain: Since he owns all the jobs including the government positions.
* MeaningfulName: His name best describes his [[{{Jerkass}} rancid personality]].
* NamesToRunAwayFromReallyFast: ''Rancid'' Rabbit.
* NewJobAsThePlotDemands: He has ''all the jobs''. What job he is doing depends on the episode.
* PetTheDog: He'll sometimes help out [=CatDog=] when it's absolutely necessary. He's not the least but antagonistic in "Flea or Die" (in which he plays a doctor), and at the end of the episode, when the duo show up at his clinic covered in fleas and begging for a flea bath, he freaks out and immediately gives them one without hesitation.
* SpeciesSurname: Rancid '''Rabbit'''.

[[folder: Eddie the Squirrel]]
-> Voiced by: Dwight Schultz
* HarmlessVillain: Of all the people who actively antagonize [=CatDog=], he's the most ineffectual and isn't really a threat.
* IneffectualSympatheticVillain: Heavy on the ineffectual, light on the sympathetic.
* InformedSpecies: He's supposed to be a squirrel?
* {{Jerkass}}
* MotorMouth: Nobody can shut the little twerp up.
* NotSoHarmlessVillain: He almost killed Lube with a tick at one point and built a giant robotic cat to get revenge on the Greasers and enslave the town.
* TheSixthRanger: Despite the Greasers dislike towards him, there are a few episodes where he is shown hanging out with them without any problems. One example is ''Rinky Dinks'' where he is a member of their ice hockey team and joins them in kicking everyone off the ice.
* SmallAnnoyingCreature
* TheTeamWannabe: He wants to be a member of the Greasers, but Cliff, Lube, and Shriek won't give him the time of day.

[[folder: Tallulah Headbank]]
-> Voiced by: Maria Bamford
* BitchInSheepsClothing: A gorgeous movie star who is also vain and snobbish.
* CatsAreMean
* CelebCrush: Cat has one on her.
* {{Jerkass}}: Noticing a pattern here?
* NiceCharacterMeanActor: Tends to play sweet love interests, but is a huge snob.
* NoCelebritiesWereHarmed: A spoof of Tallulah Bankhead.
* PetTheDog : She declares Cat her soulmate when he reveals that he has every quality she's looking for...[[YankTheDogsChain right until Cat accidentally burns her dog.]]
* RichBitch: Very rich, very nasty.
* WhatDoesHeSeeInHer: With all the hate and abuse she dishes out on Cat whenever he's around her, you'd think he would've given up on her by now.

[[folder: "The Mailman"]]
-> Voiced by: Dave Thomas
* ArchEnemy: To Dog.
* BaldOfEvil: When seen without his hat on, he is shown to be bald.
* BigBad: Of "Fistful of Mail".
* FormerlyFat: [[spoiler:As the Paperboy, he was so chubby as to be unrecognizable as a slender, sleek adult. An interesting example, as its only relevance to the plot is to reveal just why Dog didn't recognize him at first.]]
* GoldTooth: Which signals to Dog that he's [[spoiler:the Paperboy all grown up]].
* {{Jerkass}}: He picked on Dog ever since he was a puppy.
* LizardFolk: He appears to be a very fast lizard in cowboy attire.
* NiceHat: In keeping with his "Cowboy" theme.
* NoNameGiven: He's never given a name and is called "Mailman" in the credits.
* SchoolyardBullyAllGrownUp: [[spoiler:Used to be a paperboy who mocked Dog for being too slow to get the newspapers he threw.]]
* SlasherSmile: Wears one whenever he's not being a SmugSmiler.
* SmugSnake: An appropriately reptilian one too, though he's a lizard.
* SuperSpeed: His specialty. He's the first [[spoiler:and last]] mailman to surpass Dog in speed.
* UnstoppableMailman: The first mailman Dog couldn't stop. [[spoiler:Until the end, that is.]]
* VillainousBreakdown: [[spoiler:Has one after Dog defeats him.]]

!'''Spoiler Characters'''
[[folder:Spoiler Characters]]
!![=CatDog's=] parents
-> Voiced by: Billy Bob Thornton (Dad), Jane Krakowski (Mom)
* BigfootSasquatchAndYeti: [[spoiler:The mom looks like this kind of creature. None of the other characters know what she is, not even her husband.]]
* CatchPhrase: Dog got his from the mom.
* DeadpanSnarker: The dad, which is where Cat gets it. Seeing his father make the same sarcastic remark he makes is what ultimately leads Cat to accept that these two are indeed his parents.
* GenkiGirl: The mom, which is where Dog gets it. They bond almost instantly.
* GoodParents: They loved [=CatDog=] dearly, even though [[spoiler:they weren't their biological parents]]. When they were separated, the two of them spent almost their whole lives searching for their sons.
* HappilyMarried: They are clearly happy together.
* InterspeciesAdoption: [[spoiler:They adopted [=CatDog=] when the two of them were babies.]]
* InterspeciesRomance: [[spoiler:The dad's a frog, the mom is a big blue Sasquatch looking thing.]]
* LikeFatherLikeSon: Dog takes after the mom, Cat takes after the dad.
* MamaBear and PapaWolf: To [=CatDog=]; they spent years searching for them after they were separated.
* UnnamedParent: Neither of them are given a real name and are only referred to as Mom and Dad.
* WalkingSpoiler: Knowing too much about them spoils the GrandFinale.
* WhamLine: The mom has one when she finally speaks:
-->'''[=CatDog=]'s Mom:''' HI HO DIGGETY!