When his father was killed by gangsters, young John Sterling decided to become a crime-fighter. Studying chemistry, he searched for something to give him an edge in his battle. He discovered a formula that, theoretically, would give his body the properties of steel. Coating himself with the formula, he hesistated before taking the last step...diving into a cauldron of molten steel. Mustering up the courage, he jumped in and emerged with tissue as mighty and impervious as metal, with magnetic properties to boot.
Rather than adopt a secret identity per se, John decided to be Steel Sterling around-the-clock.
Although John can be affected by magic or dazed by a blow to the head, his greatest weakness are solar flares, which cause his powers to ebb. Otherwise, not even an artillery shell fired point-blank can penetrate his skin. His other powers include muscles of steel and the ability to rub his "electrolized" tongue against his teeth to tap telephone wires, the sound then coming from his mouth. Steel Sterling's costume is made of a metallic fiber that is impervious to gunfire.
In a 1983 retelling of his origin story, Sterling is hypnotized by a star, which compels him walk through the flames at an iron foundry that gives him his powers. The star thereafter leads him to a garbage pail where his costume has mysteriously been planted.
DC comics reboot
In the DC reboot of the series Steel Sterling is a retired War Veteran and highly distinguished member of the army. Owning many Purple Hearts for his courage and valor in the face of enemies he was named "Steel" Sterling due to him suffering many combat wounds but persisting in fighting. It is revealed that he is a widow and that his wife was refused medication money from their insurance and blames the company for his wife's death.
He assists The Shield
and the Justice Society of America in defending his home town of Happy Harbor from a splinter group of H.I.V.E operatives working for Dragonfly
and Baron Gestapo