The Miracle Man began his career as a cheap stage magician. He wasn't very good but he discovered he was subconsciously hypnotizing his audience into “seeing" him perform incredible tricks. One night he saw the then-new Fantastic Four sitting in the audience. He boasted his powers were greater than theirs and apparently proved it when he humiliated the Thing onstage. That night he decided it was time he used his powers to get rich as a super-criminal. He has the distinction of being the first of many foes that made of hostage of Susan Storm back in the early days of the Fantastic Four. His career came to a screeching halt when Reed Richards deduced that the Miracle Man’s powers were all illusions. A burst of light from the Human Torch blinded him and destroyed his powers.
Eventually his vision returned but not his original powers. He sought training from the Cheemuzwa Tribe, a group of Amerindian psychics. They gave him psionic powers that he used to apparently destroy the surviving tribe members. He then tried to destroy Wyatt Wingfoot’s tribe but was defeated by the timely arrival of Wyatt, the Human Torch, the Thing, and Medusa. The Cheemuzwa reappeared, explained they had actually been ghosts all along, and took the Miracle Man away to another plane where they tried to teach him to use his powers properly. He escaped once and returned to wreak havoc before he was defeated by the Thing. The Cheemuzwa blocked his powers and took him away to teach him to behave.
The Miracle Man overpowered the Cheemuzwa and used his restored powers to try to re-enact the nativity at a Native American reservation in a crazed attempt to become God. He was defeated and returned to the Cheemuzwa's custody by the Thing and Ghost Rider. 
The Miracle Man then joined a monastery. There he encountered Daimon Hellstrom and somehow gained the latter’s Darksoul. This restored his mind and all his powers. Another brief rampage followed before the Darksoul left his body. The Miracle Man finally lost his Cheemuzwa-taught powers, but retained his original hypnotic power.
Several months later he decided he needed an ally and attempted to free the Rhino, who was en route to Project: Pegasus for treatment. Coincidentally, the Thing was on the same bus that the impoverished Miracle Man was riding. The hypnotized Rhino fought the Thing but turned on Miracle Man when the latter’s hypnosis was revealed. Miracle Man was fleeing the scene when he was shot and killed by the Scourge of the underworld, who had been disguised as another passenger on the bus.
He was among those later resurrected by The Hood, initially to fight The Punisher. He clashed with the Punisher as part of the Hood's army and failed to defeat him, but escaped alive. 
The Miracle Man possessed superhuman hypnotic powers which enabled him to influence the minds of large masses of people simultaneously. Apparently, he could telepathically plant his hypnotic illusions in the minds of his victims, for they would "see" the illusions without being told what to see. The Miracle Man's hypnotic powers even worked over television, since people watching the movie premiere on television "saw" the monster model come to life as he had intended that the spectators would. The Miracle Man could not use his hypnotic powers without making eye contact with his victims either in person or over television; hence he could not use his hypnotic powers if he was blinded. The source of the Miracle Man's powers is unknown; possibly he was a mutant.
For a time, the Miracle Man possessed vast psionic abilities to manipulate matter and energy that were taught to him by the spirits of the Cheemuzwa elders. With these powers, the Miracle Man could rearrange matter, project energy blasts, and increase his own strength to superhuman levels. He could not create living beings, although he could create androids with these powers. Apparently the frequent large-scale use of these powers had adverse effects on the world's nuclear stockpiles, which have since been reversed. All of the effects that the Miracle Man caused with these powers were undone when he lost consciousness.
For a very brief time, the Miracle Man also possessed the Darksoul of Daimon Hellstrom.
Ordinarily, the Miracle Man possessed the normal human strength of a man his age, height, and build who engaged in little regular exercise. While possessing the powers taught him by the Cheemuzwa, the Miracle Man could increase his strength to superhuman levels, at least enough to match the strength of the Thing, who can lift (press) 85 tons.
The Miracle Man returned to battle the FF after he learned the secrets of animating matter from elders of the Cheemuzwa Indian tribe. Perhaps he had this ability all along but had exhausted himself in actually animating the Monster statue during the first battle. Perhaps the tribal elders helped him in regaining this power.
A character named Mr. Miracle, who is the spitting image of the Miracle Man, appeared on a view screen as an agent of the Corporation in Cage #13. These characters may or may not be somehow related.