Jenny Wakeman (XJ-9) is a teenage-robot. Designed by her mother, Dr. Nora Wakeman, as Earth's supreme protector, she possesses planet-saving weaponry and super-strength, but constantly struggles to balance heroic duties with her ultimate desire to live a normal teenage life. Despite her formidable build, Jenny has a bubbly, tomboyish, and deeply emotional personality.

Dr. Noreen "Nora" Wakeman is a brilliant, eccentric, and fiercely protective robotics scientist. As Jenny Wakeman's creator and mother, she is dedicated to defending Earth, though her overbearing parenting and struggles with teenage fads often clash with Jenny's desire for a normal life. High-energy, passionate, and brave. While deeply loving, she can be strict, stubborn, and an embarrassing parent who is entirely out of touch with modern teenage slang.

Brad Carbunkle is a main character and Jenny Wakeman's fun-loving, adventurous best friend. He is an outgoing, kind-hearted teenager who embraces the superhero life, often acting as Jenny's guide to normal adolescent experiences. He's a "ladies' man" as he calls himself and loyal. He's sixteen.

Tucker "Tuck" Cornelius Carbunkle is his full name. He is Brad Carbunkle's younger brother and one of Jenny Wakeman's closest, albeit most troublesome, human friends. Despite being a major superhero fan, he's a major scaredy cat. Though he often acts like an annoying, whiny pest, Tuck is surprisingly clever and rational. He's eight and short which is normal for a kid... Probably.

Sheldon Lee is a highly intelligent, nerdy high school student who harbors an intense, mostly unrequited crush on Jenny Wakeman (XJ-9). Despite his social awkwardness, Sheldon is a genius-level engineer. He frequently steps in to repair Jenny's complex systems and builds extravagant gadgets for her. : To prove himself and woo Jenny, Sheldon designed a high-tech robotic exoskeleton named Silver Shell. Inside this suit, his personality does a complete 180—he becomes suave, overly confident, slick, and undeniably cool. He's sixteen just like Jenny and Brad.

Brittany "Brit" Crust is a snobby, popular high schooler and a primary recurring bully at Tremorton High. As the stylish, manipulative mastermind of the "Crust Cousins" alongside her cousin Tiff, she uses her elite social status to relentlessly bully and humiliate Jenny Wakeman.

Tiffany "Tiff" Crust is the resident "street-smart punk" and co-leader of the popular bully clique at Tremorton High. She serves as the physical muscle alongside her cunning cousin, Brit. The Crust Cousins dedicate their time to making Jenny's life miserable.