Charles Xavier was the son of nuclear researcher Brian Xavier and his wife, Sharon. His mutant abilities surfaced shortly after his father died and his mother remarried. During an abusive act by his stepfather against his stepbrother Cain, Charles mentally commanded his stepfather never to raise a hand to another human being again. In the years that followed, Charles rarely used his powers, preferring to keep them hidden.

Eventually, mutants began to appear around the world and the man named Magneto emerged to lead them. At first, Charles was hesitant to side with Magneto; but he was eventually convinced that Magneto's belief that mutants should inherit the Earth was correct. Charles became Magneto's most trusted confidante. Their first order of business was to take down the island of Genosha and to free its slave mutant population. The two were successful, but Charles has not been seen since.