James Saunders, a disgruntled chemist tired of his job with the Hudson Pharmaceutical Company of West Caldwell, New Jersey, was contacted by the Grandmaster and offered superhuman powers in exchange for joining a team that would compete on his behalf. Saunders agreed, and he created a formula based on information given to him by the Grandmaster and that granted him superhuman speed. The Grandmaster then had him take the identity of the Whizzer, join the Squadron Sinister, and fight the Avengers, who themselves were pawns of the Grandmaster’s opponent, Kang The Conqueror.
Although the Squadron was defeated, the Grandmaster kept his word and returned Saunders and the others to Earth with their powers. A few months later, Saunders and the other members of the Squadron Sinister were hired by the alien geographer, Nebulon. Nebulon and the Squadron Sinister tried to melt the polar ice caps, but they were stopped by the Defenders. In the end, Doctor Strange cast a spell of amnesia over the Squadron members, causing them to forget their powers.
Saunders got his job back at Hudson Pharmaceuticals and worked there for some time until his memory was accidentally restored when the Avengers questioned him about one of the other Squadron members, Doctor Spectrum. Saunders experimented with the original formula that had given him his powers, creating a variant that increased his speed to even greater levels. He took a new name, Speed Demon and began to use his powers in various thefts, most often clashing with Spider-Man.
Later, Speed Demon joined the Sinister Syndicate, led by the Beetle (now the hero MACH-IV). During this time, he developed a rivalry with various other members of the team. The team proved short-lived, and Speed Demon rejoined their later incarnation led by Leila Davis, the wife of the villain the Ringer, which was similarly disbanded shortly after, due as much to the petty in-fighting among its members as their defeat by Spider-Man.
Deciding to branch out, Speed Demon would later participate in an event called the Bloodsport, an annual tournament held in Madipoor showcasing fighters from around the globe. During the first round, He was pitted against Wolverine (as Patch) in a Cylinder Match. Despite his best efforts and the addition to throwing knives into his arsenal, Speed Demon did not fair well. While trying to incapacitate Patch in a vortex of wind, Speed Demon was caught in the neck by one of his own throwing knives. Bleeding profusely, Saunders fell pray to Patch. While the crowd cheered for death, Patch ultimately choose not to kill his wounded opponent. Speed Demon, despite his injuries, survived.
Sometime later, He joined the villains-turned-heroes team the Thunderbolts and, with them, fought Fathom's Five, Hydra, the Purple Man, and the Avengers. Always contentious and prone to grandstanding, he seemed to serve faithfully with his teammates. But in fact, Sauders had been committing crimes in his old identity of the Whizzer, funneling it into an account to keep the Thunderbolts operational. He was originally discovered by his teammate, Blizzard, but Speed Demon bullied him into keeping it a secret. This came to a head when Saunders robbed division of Richmond Enterprises, which resulted in his former teammate Nighthawk seeking him out. Before the Thunderbolts could stop Nighthawk, a revived Squadron Sinister also arrived, and they took both Nighthawk and Speed Demon away with them. The Squadron hoped to take over the world in order to better solve the world’s problems, but they were again confronted by the Thunderbolts. Speed Demon hoped to trick the Squadron into thinking he would help them, but he turned on them, helping the Thunderbolts force them to escape. Nevertheless, Songbird ultimately kicked Speed Demon out of the Thunderbolts because of his previous robberies, claiming that what the Thunderbolts needed more were members whose hearts were behind their efforts to reform.
Speed Demon returned to the Squadron Sinister, who preferred to be called Supreme Power, who were again recruited by the Grandmaster. This time, the Grandmaster claimed that the stakes of the game would affect the entire universe, and he hoped to use the Squadron to find the Wellspring of Power, from which he drew upon to grant the Squadron their abilities. (Indeed, Speed Demon’s powers had been noticeably increasing during his time with the Thunderbolts, presumably having something to do with the Wellspring.) The Thunderbolts’ Joystick, investigating the Wellspring on behalf of Baron Zemo, intercepted Speed Demon’s attempts to track the Wellspring, and the two fought. Joystick surprised Speed Demon by suddenly exhibiting superhuman speeds even greater than his own, and she left him defeated, both his legs broken.