From Wikipedia:
Commander Steel is a fictional character and a superhero who first appeared in Steel, The Indestructible Man #1 in 1978, published by DC Comics. Created by Gerry Conway and Don Heck, the stories were set in World War II.
Heywood enlisted in the U.S. army prior to their involvement, but was still injured when saboteurs attacked his base spearheaded by the man who would become Baron Blitzkrieg. As a biology student under the tutelage of Doctor Gilbert Giles, his former professor performed extensive surgery on him with mechanized steel devices that facilitates normal human functions only on a superhuman level. He adopted the persona Steel.
Heywood soon allied himself with the All-Star Squadron and while in a field of war was later commissioned Commander Steel by President Roosevelt. He joined the Squadron for a brief period, until effects of the Crisis on Infinite Earths caused him to shift from his native Earth-Two to Earth-One, wherein he retired from his superhero career as there were no active costumed heroes at that time on his new home.
Years later, as a wealthy industrist, he incorporated the same mechanized components into his grandson Hank Heywood, III - who later joined the Justice League of America and fought Heywood along with his ally Mekanique, former allies Justice Society of America and their descendants Infinity, Inc.. Eventually, Heywood saw the error of his ways, having performed unnecessary surgeries on his grandson which caused him great pain.
After his grandson's death, Heywood resumed the mantle of Steel and has apparently died battling the supervillain Eclipso.
