Some of the DC/Marvel costumed crime fighters biographies show them to be former Olympic athletes. Who was first of them with that credential?
According to the in-universe timeline, Amazing Man (the first one, well at least DC's first) would predate any of the others mentioned so far, as he existed during the 1940's. (In reality, he wasn't published until the 80's...)
Will Everett was a promising young African-American Olympian who had competed in the 1936 Summer Olympics in Berlin, but his post-Olympic career devolved into a janitorial profession at a laboratory owned by Dr. Terry Curtis. During an accident involving the explosion of some equipment to which he was exposed (developed by the criminal mastermind the Ultra-Humanite), Everett quickly developed the ability to mimic whatever properties he touched (similar to Marvel Comics' Absorbing Man). For example, if he touched steel, then his body became composed of steel
Northstar won a gold medal in skiing by secretly using his superhuman speed, although I don't know if he would be considered "costumed" since his identity is public.
The metahuman Triathlon/3D Man (Delroy Garrett) was an Olympic track medalist whose career was derailed when it was found he used steroids. Dejected, Delroy joined the Triune Understanding to restore his faith. Unknown to him, his powers were actually the stolen superhuman abilities of the 3-D Man.
- Real Name: Delroy Garrett, Jr.
- Identity: Publicly known
- Group Affiliation: Avengers, also a member of the Triune of Understanding
- Base of Operations: Avengers Mansion
- First Appearance: AVENGERS Vol. 3, # 8
- Current Team Affiliation: Agents of Atlas (article discusses recent revival of character)
- Delroy Garrett is imbued with the abilities of the original 3-D Man. He has three times the physical abilities of a man in peak physical condition. He can also heal injuries in a third of the time that would take a peak human to heal. His perceptions (sight, hearing, smell) have been enhanced as well. He can also run at superhuman speed (just under 100 mph).
Triathlon, created by Kurt Busiek
The Triune Understanding's leader Jonathan Tremont imbued Delroy with the powers stolen from the former superhero, the 3-D Man. Delroy had no idea of the source of his new powers thinking that the teachings of the Triune had simply unlocked his superhuman potential. Delroy became the costumed superhero, Triathlon, and became the Triune's celebrity spokesman.
Mister Terrific was a gold medal Olympic decathlete before he became a costumed super hero.