Although gainfully employed as an interior decorator, Brian Hibbs nurtured a lifelong desire to be a super-villain. His fascination inexplicably fixated upon Frank Oliver, a.k.a. Kangaroo, a minor adversary of Spider-Man; after Oliver’s ignominious death, Hibbs spent years learning Kangaroo’s skills. As the new Kangaroo, he worked for the criminal Corporation in Mississippi with moderate success, and then relocated to New York to pick up where his idol left off. Caught up in a robbery spree, he was taken unaware by Spider-Man, who downed him with one punch and laughed about the encounter the rest of the day.
Hibbs escaped police custody and, using half of the wealth left to him in a trust fund, splurged on kangaroo-motif armor, complete with tail and pouch. Seeking a rematch, he was again knocked down by Spider-Man. His armor protected him, but its faulty weapon system collapsed the armor around the embarrassed criminal, whom Spider-Man left for the police. He was soon freed by the Grizzly, another of Spider-Man’s less-respected opponents, who teamed with Kangaroo, the Gibbon and the Spot as the Spider-Man Revenge Squad. The group’s motivations were divided: while Grizzly and Gibbon craved only payback for past humiliation, Kangaroo and Spot sought straightforward crime. Their dispute-ridden spree was interrupted by Spider-Man, who derided them as "the Legion of Losers," but his overconfidence left him careless enough to be defeated. Kangaroo, irritated by Grizzly’s and Gibbon’s second thoughts, lashed out at Grizzly, only to knock himself out instead. Spider-Man allowed the repentant pair to escape and hauled Kangaroo and Spot to prison, where Kangaroo exorcised his frustrations by building up his fighting skills and strength, earning the skills he hoped might later give pause to his opponents.
Soon at liberty again, Kangaroo underwent treatment seeking superhuman mutation. When this seemingly failed, he became a professional baseball player as Billy Bob Jenks, but, although he quickly rose to super-star status, he was expelled from the sport after his criminal past came to light. Returning to crime, he was quickly recaptured and imprisoned, his admittedly embarrassing super-villain career probably provoking more concern than he warranted. Incarcerated at the power-dampening Cage, Kangaroo parlayed his unaffected human-level fighting skills into prison respect. However, stress and exertion catalyzed his earlier mutation attempts, increasing his size and strength while retarding his intellect and fostering the delusional belief that he was the late Oliver; his newly increased strength might have approached superhuman level, but in the Cage there was little way to tell and less chance to use it.
When Tombstone, one of Spider-Man’s deadlier enemies, was sentenced to the Cage, Kangaroo was eager to intimidate him, but Tombstone remained unimpressed, though their brawl sparked an intense rivalry. When Tombstone was held in solitary confinement, Kangaroo terrorized his prisoner allies — Big Ben, Hypno-Hustler, and Rocket Racer — but Tombstone spread a false tip that his room could be reached via a heating vent. Kangaroo became stuck in the endeavor, leaving him to be brutalized by a prison gang, the Cruisers. Tombstone soon escaped, but Kangaroo remains in prison, remade far more than he intended.