Bob is a mixed-breed mutt who was abandoned on a highway as a puppy. After surviving as a tough, self-sufficient stray living in a mall, he has recently been adopted by Julia and her family. While he enjoys the comforts of a warm bed and belly rubs, he worries that he has grown overly soft and cowardly. He hides his insecurities behind a rebellious, tough-guy facade and flatly refuses to learn basic obedience commands or ride in cars.

Julia is a kind, patient young girl and the daughter of the park's head groundskeeper. She is Bob's primary owner and is deeply attentive to his needs, frequently taking him to visit his animal friends. She remains relentless in her efforts to train the stubborn mutt, responding to his deliberate disobedience with exasperated affection.

Ivan is a steady and thoughtful gorilla who now lives in a spacious enclosure at the wildlife sanctuary known as the park. Having endured years in a cramped mall enclosure, he serves as a calming and perceptive presence for his friends. He intuitively understands when Bob is struggling with internal fears.

Boss is Bob's long-lost sister, a street-toughened stray who has lived a harsh life without a permanent human home. Described as being tough as old jerky, she carries battle scars and has had to scavenge constantly to survive. Despite her difficult circumstances, she maintains a sage outlook on life.

Kimu is a captive wolf who represents the archetype of the untamed wild beast. With massive paws and a chilling stare, he is the complete antithesis to pampered domestic dogs. His presence forces other animals to confront their own instincts and the wildness they have lost or forgotten.

Ruby is a young, rambunctious elephant living in the Elephant Odyssey section of the park. Childlike and playful, she enjoys telling riddles to her visitors. Despite her traumatic past, she possesses an innocent spirit and a capacity for quick thinking in high-pressure situations.

George is Julia's father and the head groundskeeper at the wildlife sanctuary. He is a responsible, caring provider who accommodates his daughter's deep love for animals by allowing her to adopt Bob and visit the park.

Snickers is a pampered white poodle with a wardrobe of matching outfits and bows. She represents the epitome of human coddling, which deeply irritates the street-conscious Bob. Despite his constant teasing, she harbors an enthusiastic and slightly overwhelming affection for him.

Rowdy is Boss's young, vulnerable son. Born on the streets, he faces the harsh realities of stray life from a young age. His survival instincts are tested early on, making him heavily reliant on the protection of older animals.

Nutwit is a neighborhood squirrel who enjoys pointing out the hypocrisies of domestic pets. Observant and quick-tongued, he takes pleasure in reminding Bob that his comfortable new life is just one step away from wearing pink rain boots.

Droolius is a neglected dog kept chained in a backyard with a frequently empty water bowl. Despite enduring verbal and physical abuse from his indifferent owner, he remains heartbreakingly submissive and dedicated.

Minnie is a neighborhood hamster who observes the daily routines of the local pets. Along with her companion Moo, she notes how comfortably Bob lives, pointing out the gap between his tough-guy persona and his actual pampered existence.

Moo is a hamster who watches the neighborhood dynamics unfold alongside Minnie. Quick to point out hypocrisy, Moo helps remind Bob that he is no longer the hardened street stray he pretends to be.