Joseph Carter Jones, known to everyone as Joey, is an orphaned American teenager living with his grandmother, Virginia, in the fictional West Coast city of Center City, California. To help support his family, Joey works diligently at a local diner, a job he balances with his studies. Described as a bit scrawny for his age, Joey is neither particularly athletic nor a standout bookworm, often feeling like he does not fit in at school. Despite these circumstances, he maintains a bright and optimistic outlook, keeping his chin up and demonstrating a kind and pacifistic nature. He is, in many ways, a classic heroic archetype for his age: an underdog driven by a strong sense of compassion and a desire to protect his friends and family, believing that getting a popular new toy robot called a Heybo might be the key to changing his life for the better.

Joey's motivations are deeply rooted in selflessness and the ideal of heroism. He is not interested in glory but is driven by an earnest wish to become someone who can shield others from harm. His life changes dramatically when he recovers a broken Heybo discarded by a school bully, repairs it, and names it Heroman. After a strange bolt of lightning strikes the toy, it transforms into a giant, powerful robot that forms a psychic and empathic link with Joey. This event coincides with an invasion of Earth by an evil, insectoid alien race known as the Skrugg, forcing Joey and his new giant partner to become the planet's primary defenders.

Joey shares his life with his grandmother and his older sister, Holly. At school, his closest friend is Simon "Psy" Kaina, a classmate who uses crutches to walk and provides both moral support and tactical assistance throughout their battles. Joey also harbors a clear, unspoken crush on Lina Davis, a popular cheerleader from a wealthy family who returns his affections, much to the displeasure of her older brother, Will. Will is a football player who frequently bullies Joey, creating a classic dynamic of a rival who initially underestimates him. Their science teacher, Professor Matthew Denton, whose experiments inadvertently drew the Skrugg to Earth, becomes a key ally, using his scientific knowledge to aid Joey and Heroman.

Throughout the series, Joey's role evolves from a simple boy with a repaired toy into a true hero. His emotional state directly influences Heroman, whose power can become unstable or go berserk if Joey is overwhelmed by negative feelings. A major turning point in Joey's personal development occurs when he confronts the memory of his deceased father. He struggles with a misinterpretation of his father's death and the pressure of facing overwhelming odds alone. In the climactic battles, he finally comes to understand that being a hero does not mean shouldering every burden in solitude or sacrificing oneself needlessly, and that accepting the help of friends is a source of true strength.

In terms of abilities, Joey is not superhuman on his own. His power is channeled through a special gauntlet-like controller that forms on his left hand, which he uses to issue commands to Heroman. This device grants him several extraordinary capabilities, including the ability to generate protective force fields and move with superhuman speed. In the final confrontation of the series, Joey undergoes a dramatic transformation when his left hand merges further with the gauntlet, turning him into a powerful energy being with a massive, augmented arm. This new form grants him immense power but carries the risk of permanently corrupting him, a fate he is only able to resist by remembering his bond with Heroman and his friends.