Content Warning: This section of the guide includes discussion of illness and death.

Dog Man is the protagonist and hero of the story. He is a police officer with the head of a dog—taken from Greg the Dog—and the body of a human—taken from Officer Knight. Petey the Cat blew the pair up in a previous adventure and they were combined into one being. This gives Dog Man Officer Knight’s strength, fighting skills, and “pure heart” and Greg the Dog’s keen senses and “loyal brain.” His heart and mind make his character central to the thematic exploration of The Power of Friendship and Loyalty. Despite his strengths, Dog Man also ends up with some less-desirable qualities: He is “obsessed with balls” (11), licks and slobbers over both people and bones, and loves “to roll around in dead fish” (12). His absurd creation story and comical, contradictory qualities make him a key part of the book’s thematic depiction of The Importance of Creativity and Silliness.

His unusual origin explains why sometimes Dog Man behaves like a dog and sometimes behaves like a human. He is devoted to solving crimes and catching criminals like a human police officer and is capable of human activities like running an errand to the pet store.