George and Harold are the co-creators of the Dog Man comics. They are fifth-grade students and best friends. George loves to make up stories; he writes the plot for the Dog Man comics. Harold loves to draw; he illustrates the comics that George writes. The friends’ creation of the Dog Man comic series forms the frame narrative of Dog Man: Lord of the Fleas; in the Fore-Foreword, George and Harold complain about the books they are being assigned at school (such as William Golding’s Lord of the Flies), but they soon come to realize that they can draw ideas from these books for their comic series. George and Harold’s fun-loving and creative personalities are reflected in their creation; these are qualities that Pilkey suggests are invaluable.

Petey is a striped cat. He is a reformed villain, although he is still housed in Cat Jail for previous crimes. He cloned himself to achieve further criminal greatness; this process created Li’l Petey, who is inherently loving and kind rather than criminal. Through Li’l Petey’s goodness, Pilkey suggests that Petey is not inherently bad but that he has been shaped through unfortunate circumstances.

Petey is a dynamic character who evolves throughout the series more broadly, as well as evolving within Dog Man: Lord of the Fleas.