Personality: Jean is emotionally strong, practical, and a steadying presence to her team-mates. She also has a passionate side that can appear in battle, which makes her a dangerous opponent. She is in love with Scott, but still has simmering feelings for Wolverine.

Strength: Jean Grey possesses the normal human strength of a woman of her age, height, and build who engages in moderate regular exercise.

Fighting Skills: Good hand-to-hand combatant, coached by Wolverine; relies on psionic powers in combat.

Special Skills and Abilities: Highly adept in wielding psionic powers and a skilled pilot.

Known superhuman powers: Jean Grey is a mutant who possesses telekinetic abilities enabling her to levitate and manipulate living beings and inanimate objects psionically. The current extent of her powers is not yet known, but it is far greater than it was before her near-death in the space shuttle.

Jean Grey also possess telepathic powers enabling her to read minds, project her thoughts into the minds of others, and stun the minds of opponents with telepathic "mental bolts."

Jean Grey's powers (both telepathy and telekinesis) have been on the increase recently, and during a fight the team had with Nate Grey Jean exhibited a firey outline Phoenix. Has the Phoenix Force come back?

Finally, when Jean was eleven, a psychiatrist recommended to her parents that they consult a colleague of his, Professor Charles Xavier, who was secretly a mutant with telepathic abilities . Xavier explained to Jean, but not to her parents, that she was a mutant, and he treated her for several years. During this time he erected psychic shields in Jean's mind so that she would not be able to use her telepathic abilities until she had achieved the maturity necessary for dealing with them. Simultaneously, he taught her how to levitate and manipulate objects through psionic force. When Xavier judged that Jean had reached a certain level of mastery of her telekinetic power, he recommended to her parents that they enroll her in his newly established School for Gifted Youngsters. Unknown to Professor and Mrs. Grey, this school served as a cover for the X-Men, a team of young superhuman mutants being trained by Xavier to combat the threats posed by other mutants who used their powers against humanity. On entering the school, Jean Grey became the fifth member to join the X-Men and took the code name of Marvel Girl.

The original five X-Men remained together for several years. Shortly after she joined the team, Grey and Scott Summers, the X-Man known as Cyclops, fell in love with each other. Although neither told the other his or her true feelings for him or her for quite some time, they finally openly admitted their love for each other.

When Xavier realized that he had to remain in isolation for an extended period of time in order to make preparations to thwart an attempted invasion of Earth by the alien Z'nox, he released the psychic barriers preventing Grey from using her telepathic abilities. Grey's added maturity and her years of practice in using her telepathic powers enabled her to use her telepathic abilities from that point onwards. Hence, with Xavier otherwise occupied, she could use her own telepathic powers to aid the X-Men.

Sometime later, after Xavier had recruited several new members for the X-Men, Grey and some of the other X-Men decided to leave the group in order to lead their own lives. Scott Summers, however, remained in the X-Men and he and Grey continued their romantic relationship. Shortly after she left the team, Grey and the then current members of the X-Men were kidnapped by Steven Lang's Sentinels and taken aboard Lang's space station. After defeating Lang the X-Men had to escape back to Earth aboard a space shuttle during a solar radiation storm. The craft's pilot had to sit in an area without enough shielding to protect him or her from the lethal radiation. Grey volunteered to be pilot, but while guiding the shuttle to Earth, the solar radiation finally proved to be too great for Grey to hold back any longer with her powers. She began to succumb to the radiation's lethal effects.

It was long believed that Grey had indeed died aboard the space shuttle but became linked with a primal energy force known as the "phoenix-force" which recreated and reentered her body, The vastly more powerful being took the code name Phoenix. Phoenix joined the X-Men, but Grey had not had the proper training for coping with such immense power. At first Grey's strong moral sense kept the phoenix force under control, and usually subconsciously prevented her from using her powers beyond a certain limit. But then Phoenix fell victim to psychic manipulation by Mastermind, who was attempting to prove his worthiness to become a member of the Inner Circle of the Hellfire Club by mesmerizing Phoenix into becoming its new Black Queen. He psychically induced dark, repressed desires from within Grey's consciousness to come to the surface of Phoenix's mind, submerging Grey's true normal personality. Phoenix finally freed herself of Mastermind's control, but was unable to prevent the dark side of Grey's personality with the full power of the phoenix-force behind it, from overwhelming her, not having had the training necessary to repress it. Grey's true personality was submerged more fully than before, and Phoenix became the malevolent Dark Phoenix. After Dark Phoenix wreaked incredible devastation, Grey's true personality reasserted control of Phoenix once more, and, before Cyclops' horrified eyes, Phoenix committed suicide rather than revert to Dark Phoenix. Summers mourned Grey, and eventually married Madelyne Pryor, who greatly resembled her.

It was later revealed that Grey did not die, nor had she ever become Phoenix. The phoenix-force responded to Grey's anguish and telepathic calls for help as she was dying aboard the space shuttle, and appeared before her, shaping its form and consciousness after Grey's own. The phoenix-force told Grey that she was dying, but that by taking the phoenix-force's hands, Grey would gain her "heart's desire." What Grey most wanted was to save the lives of the X-Men and herself. She held onto the phoenix-force's arm and fell into a coma-like state. Simultaneously, the phoenix-force fully took on both the form and the memories and personality of Jean Grey. The phoenix-force used its powers to ensure the survival of the X-Men in their return to Earth and crash landing in Jamaica Bay off New York City. It was also responsible for casting Grey into a coma-like state and placing her within a pod like construction, which rested for years at the bottom of Jamaica Bay while Grey's injuries healed completely. Thus the phoenix-force fulfilled its pledge to Grey. The phoenix-force creature compelled itself to believe it was indeed Grey, whose personality it had assumed. Indeed, it had imitated Grey's consciousness so perfectly that not even Xavier realized the imposture. It has been theorized that it was the phoenix-entity's own power rebelling against the duplicate of Grey's personality it had given itself that caused it to become Dark Phoenix. When Phoenix committed suicide, it was acting exactly as Grey herself would have done under the circumstances, since it had endowed itself with an exact copy of Grey's personality.

Many months after Phoenix's death, the Avengers found Grey's pod beneath Jamaica Bay and brought it to the Fantastic Four for study. Grey released herself from the pod, at first unable to remember her encounter with the phoenix-force, but with the help of the Avengers and Fantastic Four, she recalled what had happened and learned what happened to Phoenix.

Grey was reunited with her fellow founding X-Men members, the Angel, Beast, Cyclops, and Iceman. She was greatly disturbed to learn of the current wave of anti-mutant sentiment in the country, Xavier's recent disappearance, and the fact that the then current X-Men were now working alongside Magneto, the original X-Men's greatest foe. Because the others agreed with Grey that they should do something about the current situation of mutants, the five friends founded a new organization to help other superhuman mutants, X-Factor. Later, after Professor Xavier returned from a long sojourn in space with the Starjammers, Jean and the other members of X-Factor rejoined the X-Men.

While Jean had been in suspended animation Scott had married Madelyne Pryor, a clone of Jean created by Mr. Sinister. Eventually Pryor went mad, developed vast powers, and became known as the Goblin Queen. The Goblin Queen died in combat with Jean.