Here are the list of characters that appear in Rocko's Modern Life.
Rocko (voiced by Carlos Alazraqui): a wallaby who has emigrated to the United States from Australia who works at Kind of a Lot O' Comics. He has unreasonable bad luck and treatment from others in most episodes. Though he is one of the most kind hearted person. Rocko is often known to play stupid like he does not know what is going on.
- Spunky (voiced by Carlos Alazraqui): Rocko's pet dog who is white with a black spot. He willingly eats almost anything he sees, which has repeatedly gotten him and Rocko into trouble. Spunky is also known to sit with his legs up in a 240 degree position.
Heffer Wolfe (voiced by Tom Kenny): Rocko's best friend, a happy-go-lucky and not-too-bright steer whom he met in high school. Heffer loves to eat and party. Strangely, even though Heffer is male, he has been shown on a number of occasions to have udders. As his last name suggests, he was raised by a family of wolves who decided not to eat him as a child and adopted him instead. Heffer is also known to have a double life. When Filburt was having children, some of his children had the appearance of Heffer, which everyone seemed stunned and suspicious.
Filburt Shellbach (voiced by Mr. Lawrence): Rocko's other best friend, a neurotic turtle who started out as a supporting character and became a main character in the second season. He lives in a trailer and has had a myriad of jobs. Filburt has an extremely weak stomach and even the slightest wrong movements can give him indigestion. Filburt also seems to have an obsession with fishsticks. He was married to Dr. Hutchison in the shows third season, with whom he has four children. Among Filburt's catchphrases are "Oh fishsticks!" and "I'm nauseous... I'm nauseous... "
The Bigheads: The Big heads are known to be odd. They are also known to act very sexual.Though it is very discrete and the kids probably do not know what is happening. In one particular episode it is shown that Ed and his wife, Bev, were high and chasing each other around like zombies.
- Edward Bighead (voiced by Charlie Adler): A grumpy old toad who is Rocko's neighbor. He hates Rocko despite Rocko normally acting nice to him. Ed works at the large corporation Conglom-O. Ed seems to have very bad luck wherever he goes and thus is very cynical. He hates his life, leading to his catchphrase "I hate my life."
- Bev Bighead (voiced by Charlie Adler): Ed's wife, a boisterous redhead (whose voices sounds close to that of Harvey Fierstein) who enjoys flirting with other men a profanity to their marriage. In the controversial episode "Leap Frogs", she unsuccessfully attempted to seduce Rocko.
- Ralph Bighead (voiced by Joe Murray): Ed and Bev Bighead's estranged son. He was disowned by Ed when he revealed that he wished to move to Holl-o-Wood and become a cartoonist, rather than follow in his father's footsteps and work for Conglom-O. Ralph's career found success with the creation of his hit cartoon The Fatheads which starred a married couple that appeared to be a highly unflattering parody of his parents. He and Ed finally reunited at Ed and Bev's anniversary party with the help of Rocko and his friends, ending the long-standing rift.
Chuck & Leon
Chuck & Leon (voiced by Carlos Alazraqui and Tom Kenny): Two twin chameleons who, like their species, adapt very well to many situations usually to make money. They run a variety of businesses throughout the show. Both have Scandinavian accents but use American accents in their scams.
- Paula Hutchison: (voiced by Linda Wallem): Dr. Hutchison is a cat. She married Filburt in the third season of the show, much to their respective families' annoyances. She soon gave birth to four children: three sons and one daughter. She has a variety of jobs, including being a dentist, a surgeon, and a canine nutritionist and has a hook for one of her hands, possibly from an accident that caused that hand to be amputated. Despite that handicap, Dr. Hutchinson is surprisingly level-headed and is prone to chuckling hysterically.
- Widow Hutchison (Voiced by Kevin Meany): is Dr. Hutchison's mother
- Mr. Smitty (voiced by Tom Kenny): is Rocko's boss. He is a smoldering old toad who owns Kind of a Lot o' Comics. He detests his employees even be a second late, and fires them for repeating this act. He apparently lives next door to the comic shop, but drives there anyway to take the parking space in front of the store. When his employees ask for a raise, he convinces them to accept Employee of the Month instead.
- George Wolfe: George is Heffer's father, he is often tempermental and angry all the time.
- Virginia Wolfe: Virginia is Heffer's mother, she is known to treat Heffer like a adolecent. Virginia twitches when she is in a stressful moment such as a fight.
- Peter Wolfe: Peter wolfe is a homosexual male. In a particular episode he is dressed as a cheerleader and a carhorn honks. It is a cliche used in TV shows during the 70's such as The Brady Bunch. Another episode it shows peter wolfe in female clothes and George wolfe screams. Then Peter says "oh sure judge". Which he is talking about being prosecuted for being a homosexual (stereotypical).
- Cindy Wolfe: Cindy wolfe is the stereotypical 90's teenage girl. She has adopted the gothic punk culture.
- Hiram Wolfe: (voiced by Chuck Adler), who hates walabys (Rocko's specie), and pretty much any other specie. Hiram is blind as a bat. Hiram always call Rocko a beaver. As seasons pass Hiram ages too and he is known to be turning more machine each time scean (such as a pacer, blood transfusion,etc.) His full name might be Hiram William Wolfe.
- Grandma Wolfe (voiced by Carlos Alazraqui) Their grandmother is desceased and spending eternity in Heck. In the episode Heff in a Handbasket, she refused to spend her afterlife with Heffer saying that he would ruin her peace and quiet.
Mr. Dupette (voiced by Charlie Adler): The Chief Executive Officer (CEO) of Conglom-O, he is the self-described "slimy boss" of Ed Bighead and enjoys picking his nose. He is almost never seen without his assistant, Noway Jose. He was also once the owner of the Super Lot o' Comics store where Rocko worked before moving to "Kind of a Lot o' Comics."
Bloaty and Squirmy
Bloaty the Tick (voiced by Tom Kenny) and Squirmy the Ringworm: (voiced by Carlos Alazraqui) Two parasites who live on and in Spunky. Sometimes, entire episodes revolve around their odd couple relationship. It is often done as a parody of The Honeymooners.
Really Really Big Man
Really Really Big Man (voiced by Tom Kenny): an insectoid superhero who lives in O-Town. He is very big and depicted as a parody of super heroes, especially Superman.
Wallace (voiced by Tom Kenny): a large elephant who works at the Pizza Face restaurant. He once almost got into a brawl with Heffer but was stopped at the last moment by his boss. Seemingly aggressive, he has a meek voice.
Peaches (voiced by Tom Kenny): Works for Satan; he's in charge of "Heck." He has attempted to lure Heffer into "Heck" several times but has repeatedly failed to do so. Due to his failure at letting Heffer be released, he was punished by being forced to star in his own cartoon show: Peaches' Modern Life.
Gladys Hippo (voiced by Charlie Adler): a large female hippo. Rocko apparently has a bad habit of accidentally crashing into her at public places upon which she screams "How dare you!" and proceeds to physically retaliate.
Flecko (voiced by Tom Kenny): a fly with a glass eye who lives in Rocko's property.
Earl: a mutt, initially homeless, who enjoys mauling Rocko, Ed Bighead, the mailman, and basically anything else that is alive. He was adopted by Bev Bighead in the second season. He was first used as a drawing for a MTV ad in 1989, just like Heffer.
Wild Pig (voiced by Charlie Adler): Makes various cameos during the series and his catchphrase is "I'm a wild pig!".