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. She constantly saves Earth from evil threats, aliens, and monsters. She deals with typical teen rebellion, angst, and a desire to fit in. She gets annoyed usually when Brad or Tuck make a situation worse by not listening to her.

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. Highly brilliant yet eccentric, scatterbrained, and prone to building overly complex gadgets or robotic countermeasures. She views herself as Jenny’s actual mother, though their relationship swings between overprotective nagging and genuine mutual care. Constantly pressures Jenny to prioritize global protection over high school social life.

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 is brave, loyal, and kind, but can also be stubborn, reckless, and a bit dim-witted at times. Brad likes to think of himself as a smooth talker who is great with girls, though his romantic attempts usually end in rejection. 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. Cunning, manipulative, arrogant, vain, and vindictive. While Tiff acts as the rougher muscle, Brit is sophisticated, posh, and prefers passive-aggressive or intricate plots to humiliate Jenny. She's sophisticated styling, trendy high-end fashion, and a sharp, snobby demeanor. Despite their tough exterior, Brit is deathly afraid of heights (while Tiff fears spiders, and both are terrified of nerds).

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. Despite her tough-girl act, both Crust cousins are easily terrified by specific weaknesses, with Tiff having a particular phobia of spiders.

Dr. Mogg shares a bitter, petty rivalry with Dr. Nora Wakeman dating back to their school days. Snide and conceited, he is famously accused of stealing Wakeman’s ideas and created his own robot "son," YK-9 (Kenny), to rival Jenny Wakeman. Nora insists Mogg built his entire career by ripping off her blueprints and ideas, though Mogg claims he merely "perfected" them. He is snide, condescending, and passive-aggressively competitive, though not genuinely evil or villainous. His full name is Phineas Mogg.

Kenny (model designation YK-9) is a bulky, white-and-indigo teenage robot who secretly behaves like a domesticated dog, a pun on his K-9 unit name. He was made by Dr. Mogg. Large and athletic physique resembling a football player or martial artist. White metal skin with indigo hair-like appendages and clothing features. Fold flat down like human hair in normal mode, but pop up into triangular dog ears in canine mode. Constantly sniffs people, shows affection with his tongue, and exhibits obsessions with fire hydrants.Sweet, deeply loyal, and romantic toward Jenny, initially impressing her with his charm and popularity. He possesses enhanced sensory perception, high-frequency hearing, and a powerful sense of smell superior to a bloodhound.