Atom Smasher, is a lot like the X-Men's Colossus: He's big and strong, but conflicted, and has made terrible decisions. He has been a villain a couple times (at least once) and his best arc was him acting as a mentor to young members of the JSA so they wouldn't make his mistakes.
Al Rothstein is a super-hero with the ability to grow in size and incredible strength. Son of the Golden Age hero The Atom, he is part of a costumed legacy. Originally he used the name Nuklon, although he later evolved to become Atom Smasher.