Nothing is know about Mastermind's life before the time when, while working as a carnival mentalist, he was enlist by magneto as a member of his Brotherhood Of Evil Mutants.

At this time Magneto sought to protect his fellow superhuman mutants from persecution by normal human being by conquering humanity and ruling the world himself.

The other members of the Brotherhood where is allies in pursuit of his goals.

As a member of the Brotherhood, Mastermind battled the original X-men repeatedly, but the X-men continually thwarted Magneto and the Brotherhood.

Finally Magneto attempted to enlist the enigmatic alien being know as the Stranger as an ally.

Angered, the Stranger transformed Mastermind into stone and transported Magneto, he captured, to another planet.

Wyngarde is responsible for awakening the Dark Phoenix. He used his illusion abilities to seduce Jean Grey to become his Black Queen in the famous arc Dark Phoenix. He was driven insane by the Dark Phoenix durnig this arc too.

After being cured of his insanity, Mastermind attempted to get revenge on all the people that hurt him, but was eventually stopped by Cyclops.

Mastermind later contracted the Legacy Virus. His last wish was for Jean Grey to forgive him for all the evil things he did to her.

Later in a flashback, it was revealed that Mastermind, after being ordered by the U.S. Military, was responsible for creating the Sentry's evil persona, the Void.

Powers

Mastermind has the mutant ability to telepathically create utterly convincing illusions. The illusions he creates are so realistic that even people who know that they are illusions still have much difficulty ignoring them (for instance, even if a person knows that the brick wall they see in front of them is an illusion, they would still have much difficulty getting themselves to walk through it). Mastermind's illusions are also so convincing that he can cause people to die by giving them an illusion that they have been killed (for instance, he once killed someone by giving them the illusion that they had drowned in water. The illusion was so realistic that, even though there was no water, the victim ceased breathing and died).