Animated characters • Ace Hart (voiced by
Ron White) - A
German Shepherd who is a
private eye detective. • Rosie O'Gravy (voiced by
Elizabeth Hanna) - A beautiful
Rough Collie who is the chief of
detectives and Ace's love interest. • Eddie (voiced by
Stuart Stone) - An
English Springer Spaniel news-pup who often tags along on Ace Hart's cases. • Bugsy Vile (voiced by
John Stocker) - A
bulldog who is a
crime boss. As the "Dogfather of Crime", he is the archenemy of Ace Hart. • Frisky (voiced by James Rankin) - A
chihuahua who is Bugsy Vile's excitable henchman. • Mad Dog (voiced by
Stephen Ouimette) - Bugsy Vile's psychotic
mongrel henchman. • Bruiser (voiced by Howard Jerome) - Bruiser is a bulldog who is Bugsy Vile's tough nephew and henchman. • Kitty (voiced by
Paulina Gillis) - A female
cat who serves as Bugsy's
gun moll. She owns The Kitty Cat Club which is often used as a hideout and front for Bugsy Vile's group. •
Baron Von Rottweiler (voiced by
Dan Hennessey) - A villainous German
Rottweiler who is the secondary enemy of Ace Hart. • Leon Burger - A
dachshund who serves as
valet and henchman to Baron Von Rottweiler. He doesn't talk for some reason. •
Mayor Kickbark (voiced by
Stephen Ouimette) - The Mayor of Dog City. He is always undermining Rosie O'Gravy. • Spunky the Flunky (voiced by
John Stocker) - Mayor Kickbark's aide. • Dot (voiced by
Tara Charendoff) - Rosie O'Gravy's cute and lovely niece. She often appears with Rosie in "The Adventures of Rosie and Dot" segments. Her only dialogue was "Why". • Steven (voiced by
George Buza) - Steven was a canine
watchman who was often seen in the animated segment with Yves. • Yves (voiced by
Rino Romano) - A
cat burglar who debuted in the third season. He would try to steal something only to get thwarted comically by Steven. • Sam Spayed - An old
police dog who served as a teacher and father figure to the young Ace Hart. His name is a pun on the
Dashiell Hammett character
Sam Spade. • Surelick Bones - An English
bloodhound detective who was a rival to Ace until he was exposed as an art thief. Before Eliot worked on the cartoon about this Surelick Bones, Artie was a fan of the different stories about him. His name is a spoof of
Sherlock Holmes. • Woof Pack - A team of superhero dogs. The group was featured in comic vignettes, approaching mundane tasks like grocery shopping from a superheroic perspective. • Watch Dog (voiced by
Don Francks) - Watchdog is a superhero who is a parody of
Batman where his name is a take on
Alan Moore's graphic novel
Watchmen. Watch Dog carries hourglasses which act as gas canisters, and constantly uses time and clock related gadgets and metaphors. In "Who Watches the Watch Dog," Watch Dog's creator Fob Canine (a caricature of
Bob Kane) posed as Watch Dog where he has his fellow comic book artist pose as the Labrador Gang in order to get Watch Dog to be popular again. Watch Dog is also the leader of the superhero group called the Woof Pack when the "Woof Pack" segments debuted in Season 3. • Plastic Lassie - A
collie with the power of elasticity and member of the Woof Pack. • Pectoral Pooch - A dog with super-strength and member of the Woof Pack. • Hear Boy (voiced by
Len Carlson) - A sound-sensitive superhero and member of the Woof Pack. • Wonder Whelp - The smallest, and youngest member of the Woof Pack.
Live-action characters • Eliot Shag (performed by
Kevin Clash) - A
German Shepherd who is the animator of Ace Hart's adventures. He often communicates with Ace Hart and would be interrupted by his girlfriend or Bruno. In "Who Watches the Watch Dog," it is revealed that Elliot is a fan of a superhero called the Hooded Hound. Seeing as Eliot is a Live-Hand Muppet, Kevin Clash is assisted in operating Eliot by Don Reardon who operates Eliot's right hand. Clash also voices Eliot's animated form in the episodes "In Your Dreams" and "The Dog Days of Summer Vacation". • Artie Springer (performed by
Joey Mazzarino) - An
English Springer Spaniel, Artie Springer is Eliot's young friend and son of Terri Springer. His favorite
squeaky toy, a yellow rabbit called Mr Mookie, eventually starred in its own cartoon. Artie's puppet was previously seen as a background character in the original special. He served as the inspiration for Eddie. • Colleen Barker (performed by
Fran Brill) - A
Rough Collie who is Eliot's neighbor and girlfriend. She is said to have moved away from the apartment when the character was dropped by Season Two. She was the first inspiration for Rosie O'Gravy. • Terri Springer (performed by
Fran Brill) - Terri Springer is an
English Springer Spaniel who debuts in Season Two. She is Eliot's neighbor, Artie's mother, and a beautiful businesswoman. She served as the new inspiration for Rosie O'Gravy. • Bruno (performed by
Brian Muehl) - Bruno is a
bulldog who is the surly
building superintendent of the apartment that Eliot lives in and has a tendency to hassle Elliot. He served as the inspiration for Bugsy Vile. • Bowser (performed by
David Rudman) - Bowser is a
St. Bernard who is the hulking slow-witted
handyman and Bruno's assistant who has a tendency to aide or hinder him. He served as the inspiration for Bruiser. • Ms. Fluffé (performed by
Kathryn Mullen in season one,
Lisa Buckley in later seasons) - A
cat who is the
landlady of the apartment that Eliot lives in. Ms. Fluffé often comes in conflict with Bruno over building policies and his tendency towards incompetence where Bruno generally kowtows to her. She served as the inspiration for Kitty. ==Episodes==