Atom Smasher (sometimes spelled with a hyphen) is a superhero in the DC Comics Universe.

The godson of Al Pratt, the Golden Age Atom, Albert Rothstein acquired his mutant powers of super-strength and control over his molecular structure (allowing him to alter the size and density of his body) from his grandfather, a reluctant supervillain known as Cyclotron, allowing him to fight crime first as Nuklon, and then, later, as Atom Smasher. Albert was a charter member of Infinity Inc. and subsequently served in the Justice League and the Justice Society of America.

Atom Smasher's mother was murdered in a plane crash engineered by Kobra. Al replaced his mother with a weakened Extant, saving his mother's life but murdering the supervillain. He became displeased with the JSA's inability to catch criminals, especially Kobra, and teamed up with Black Adam's group to retake Khandaq. He fought against his JSA teammates in Khandaq, though he has begun to go back to the side of good.