Jason was portrayed by Michael Reid McKay.
As a child, Jason grew up resenting his parents because he blamed them for his mutant condition. His father William enroled him in Professor Charles Xavier's School For Gifted Youngsters, an institute that taught mutants how to properly control their powers for the benefit of society. However, William had hoped that Xavier would be able to cure Jason of his mutation, but the professor possessed neither the knowledge, nor the interest, to cure mutants, claiming that mutation was not a disease but the next step in mankind's evolution. Jason returned home to his parents and tormented them with his mental abilities, projecting horrifying images into their minds. His mother was driven to madness by his illusions and commited suicide, which further fueled William's hatred of all mutants.
Some time after the death of his wife, William had his son imprisoned and experimented upon. He discovered that Jason's power was fueled by a chemical agent produced within his brain and that this chemical could be used as a mind-controlling agent. Believing that his son could be instrumental in solving the "mutant problem", William had Jason lobotomized and turned his own power against him, reducing his son to a crippled, obedient servant. He then began regularly extracting Jason's cerebral fluids and used it to brainwash several mutants into doing his bidding.
Many years later, William devised a plan to annihilate mutantkind in one fell swoop. After using his son's mind-controlling agent on captive mutant terrorist Magneto, he learned about the X-Men and the psychic amplifier device known as Cerebro. Knowing that Cerebro could allow him to achieve his goals, he abducted Professor Charles Xavier and broke into the X-Men's mansion in order to steal vital components from Cerebro so that he could build one of his own. Cerebro could only be operated by a telepathic mutant, hence the abduction of Xavier. After capturing Xavier, Stryker outfitted him with a device to prevent him from attacking the colonel's mind. He then commanded Jason to bring Xavier under his control and Jason projected a psychic image of a scared little girl into the professor's mind. In the illusion, the girl asked the professor to find her friends using Cerebro, and Xavier, unable to fight back, entered Stryker's Cerebro chamber and used it to try and locate every mutant on Earth. With enough concentration, Xavier would be able to kill the entire mutant population all at once.
When the X-Men and Magneto broke into Stryker's base at Alkali Lake, Magneto was able to reach the Cerebro chamber and stop Jason from carrying out Stryker's plan. With the special helmet he wore, Magneto was immune to Jason's psychic abilities and he brought in Mystique, who transformed herself into William and commanded Jason to manipulate Xavier into targetting normal humans instead of mutants. Jason complied with the order and Magneto and Mystique left him and Xavier inside the chamber to make their escape.
The X-Men later found the Cerebro chamber and discovered what Magneto had done. Storm and Nightcrawler teleported inside the chamber where they saw not Jason or the professor, but the little girl that Jason had projected into Xavier's mind. Storm knew it was an illusion and generated a blizzard inside the chamber to break Jason's concentration, shattering the illusion and releasing his control of the professor. Storm and Nightcrawler then took Xavier and the X-Men made their escape. Jason, on the other hand, was left to die when the base began flooding after the dam ruptured.
- The character of Jason Stryker seems to be based on the Marvel Comics character Jason Wyngarde, aka Mastermind. Mastermind was also a villain (though a willing one rather than being someone's pawn) and possesses the same powers of mental illusions.