Rudolph Bartholomew "Rudy" Tabootie
Voiced by: Elizabeth DailyThe main protagonist of the show. In the original Oh Yeah! Cartoons shorts, he was eight years old when he first discovered ChalkZone by finding a piece of magic chalk in his classroom. Come the show, he is now ten years old, and continues to have adventures in ChalkZone.
Penelope Victoria "Penny" Sanchez
Voiced by: Hynden WalchRudy's friend/love interest. She is a studious ten-year old girl who was introduced to the world of ChalkZone when Reggie Bullnerd erased her scientific formula, and Rudy took her into ChalkZone in an attempt to get it back. Since then, she's often accompanied Rudy on his misadventures.
Voiced by: Candi MiloA superhero-like zoner created by Rudy when he was eight years old. When Rudy entered ChalkZone, he discovered Snap and the two have gone on adventures as close friends. There are times when Snap entered the real word, either on purpose, or dragged there by being kidnapped.
Voiced by: Jim CummingsThe most recurring antagonist on the show. Skrawl was originally going to be a birthday gift by Rudy to a kid at a birthday party, but Reggie Bullnerd and his friends ruined it, and Rudy erased him into ChalkZone. Ever since then, Skrawl has blamed Rudy for his grotesque appearance, and constantly schemes to bring him down.
Reginald Clark "Reggie" Bullnerd
Voiced by: Candi Milo
Mr. Horace T. Wilter
Voiced by: Robert Cait
Voiced by: Jess Harnell
Voiced by: Miriam Flynn
Voiced by: Rodger Bumpass
Voiced by: Iona Morris
Voiced by: Jeff Bennett
Officer O' Neil
Voiced by: Rosslynn Taylor