Super-villain published by Marvel Comics. The Leader first appeared in Tales to Astonish #62.

Samuel Stern worked for the U.S. government, disposing of hazardous radioactive material. Stern was an average man with no special skills and no special traits, living a life of quiet desperation. One day, while disposing of a canister containing material with a high amount of gamma radiation, Stern was exposed to huge dose of gamma rays, when the canister exploded.

Stern was taken to a government hospital for treatment. Over the next few weeks, it became apparent that the radiation had triggered a mutation within Stern, causing his intellect to grow at an astounding rate. He began to read voraciously and remember everything he read. Soon, his body began to change, with his cranium growing to accommodate his growing brain and his skin beginning to turn green.

Stern escaped the government hospital and began to use his newfound intellect for evil purposes Calling himself the Leader, Stern came into conflict with the incredible Hulk. The two have clashed on a number of occasions with the Leader often times seemingly coming up with the upper hand.

The Leader over the years has employed a number of inventions to aid in his quest for world domination. He created a type of android made of an advanced polymer. The Leader created them in bulk, assuring that they could overcome even the toughest opponent, just by their sheer numbers.

Apart from his advanced intellect, the Leader also possesses other abilites. His massive brain allows him to attack others with mental blasts and also to take control of others. After an episode where Stern returned to original form after the effects of his initial radiation exposure wore off, Stern plotted and had himself reexposed to a blast of gamma radiation. Stern mutated again, but this time with a different appearance. He continued to have the ability to control others, but he now seems limited to those he can touch.

The leader has teamed with other villains over the years in pursuit of his goals. He has used the Rhino and the Abomination as pawns in different projects, as well as the former Hulkbusters, Rock and Redeemer.