David Mitchell was an ordinary civilian kidnapped by Agent Axis, a Nazi villain who had fused three different personalities into one body. Agent Axis wanted to use Mitchell as a hostage and a guinea pig for his machine that could enhance human abilities. However, things did not go as planned, and the machine gave Mitchell the power to spin at incredible speeds, creating whirlwinds and sonic booms. Mitchell escaped from the device and helped the Invaders, a team of World War II heroes, to defeat Agent Axis. He then joined the Kid Commandos, a group of young sidekicks led by Bucky Barnes, the original partner of Captain America. Mitchell adopted the name Human Top and wore a red and yellow costume with a spinning top motif.

As the Human Top, Mitchell fought alongside the Kid Commandos and the Invaders against various threats during World War II, such as Baron Blood, Master Man, Warrior Woman, U-Man, and Lady Lotus. He also befriended Golden Girl, another Kid Commandos member with super strength and durability. Mitchell had a crush on her, but she only saw him as a friend. After the war ended, Mitchell retired from super heroics and lived an everyday life.

Mitchell resurfaced decades later as a resident of Valhalla Villas, a retirement home for former heroes and villains in Miami. He was among the residents temporarily de-aged by Mary Morgan, a former Asgardian goddess who used a magical relic to restore their youth and powers during an incursion event that threatened to destroy their world. Mitchell briefly resumed his role as the Human Top and helped Ant-Man and other heroes to stop Morgan’s plan and save their reality.