Jean first discovered her mutant powers at age 10. Her best school friend, Annie Richardson was struck by an automobile. Jeans psychic powers awakened and she read the mind of her best friend, who was dying. She went into an autistic state, and parents took her to Xavier. There Xavier tutored her for years to help coax her out of her emotional shell. Xavier later recruited her into the first X-Men team. Yes, even though she was the fifth and last founding member of the X-Men, she was the first of his mutant students. At firstshe was only telepathic, but later was able to better harness her powers of telekinetics.

She has been in love with Scott Summers on first sight, but since he was too shy the relation took almost 60 issues to start and more than 300 till marriage. Between both moments, Jean has 'died' several times. First, she was kidnapped by Trask and taken to space by the sentinels. The shuttle they had to return to earth was severly damaged, and the only one who could pilot it was Peter Corbeau, a human. He wouldn't be able to stand a minute of the cosmic rays so she sacrificed herself, absorbing his knowledge. The shuttle came into a bay, and Jean reappeared as the powerful Phoenix. Since her human body was not enough to contain so much energy, she became corrupted (with a little help from Master Mind) and joined the Hellfire Club as the Black Queen and then as Dark Phoenix, whose hunger was infinite. Realizing that it was her or the rest of the universe, Jean sacrificed herself again in the Blue Zone of the Moon. (Phoenix wasn't really Jean, but a being who took her shape, while she was recovering from her injures in the bottom of the bay.)

Jean was found by the 4F, just to discover that Scott had married another woman and had a child. Of course, that's not all, for Madelyne Pryor (Scott's wife) was really a clone of Jean breed by Mr. Sinister, who turned into the Goblin Queen during Inferno. Madelyne died at the end of that adventure, joining her memories and Phoenix's into Jean's mind. For a while, the old X-Men were X-Factor, but they came into the old group after the fight against the Shadow King.