Leonard Samson, born Leonard Skivorski, Jr., earned a PhD in psychology. While attempting to cure Bruce Banner, Samson irradiated himself with gamma radiation. He continued to practice psychology, usually called Doc Samson by his patients.
Later, M.O.D.O.K. placed Samson under mind control, splitting his pre-gamma radiation, powerless personality ("Leonard") from his more Hulk-like, powered identity ("Samson").