Charles Francis Xavier is the mutant son of wealthy nuclear researcher, Dr. Brian Xavier, and his wife, Sharon Marko. After Dr. Xavier's death in an accident, Sharon married his colleague, Dr. Kurt Marko, whose son by a previous marriage, Cain Marko, bullied the young Charles. Dr. Marko favored the gentle, smart Charles to his own son. Sharon married Dr. Marko because she believed that it would be best for Charles. Charles' telepathic powers began emerging when he was still a boy, around ten, and, as he grew older, he learned to control them. With his powers, Charles had discovered that Dr. Marko cared only about his mother's money. Dr. Marko quickly grew neglectful of Sharon, driving her to alcoholism, and abused both Sharon and Cain. Charles would link his mind to his mother's, in a effort to share the abuse with her and alleviate it. Charles, once, used his telepathic powers to read Cain's mind and explore the extent of his psychological damage, which only led to Cain becoming more aggressive toward him and Charles feeling Cain's pain firsthand. Sharon died soon after and a fight erupted between Cain and Charles, that caused some of Dr. Marko's lab equipment to explode. Mortally wounded, Dr. Marko dragged the two children out before dying. Due to the immense psychic energies emanating from Charles' head, he became bald at a young age.
A brilliant student intent on undertaking graduate studies, Charles entered England's Oxford University, where he met and fell in love with a young Scotswoman, named Moira Kinross. Their passionate discussions on genetic mutation gave way to an equally passionate romance. It had also been hinted that Mister Sinister interfered with Moira's and Xavier's relationship, as he was posing as a professor at Oxford at the time. Charles and Moira planned to be married, but after finishing his work at Oxford, Xavier was drafted and sent to Asia during the Korean War. There, Xavier and his step-brother, Cain, served in the same unit. Xavier witnessed how Marko found the mystical ruby in the Temple of Cyttorak, that transformed him into the superhuman Juggernaut. Just then, enemy high explosive bombardment caused a cave-in and Marko was buried under several thousand tons of rock. Xavier survived and returned to his unit. Xavier also served alongside Kitty Pryde's father, Carmen Pryde, on search and rescue missions, where he earned the nickname, The Good Shepherd.
Deeply depressed when Moira broke off their engagement without explanation, after inheriting his family's considerable wealth, Xavier began traveling abroad. After leaving the army, Xavier later discovered that Moira married her old boyfriend, Joseph MacTaggert, who abused her. While in Cairo, Egypt, Xavier met the young pickpocket, Ororo Munroe, and, while making mental contact with her, battled Amahl Farouk, the Shadow King, the first evil mutant he had ever met. This meeting led to the visionary Xavier's decision to devote his life to protecting humanity from evil mutants and safeguarding innocent mutants from human oppression, believing that both could peacefully coexist. Xavier, who acknowledged she was a mutant from her brainwaves, declined to contact Ororo at this point, not wanting to shock the young woman with the true nature of her powers.
Xavier next went to Haifa, Israel to meet with the head of a clinic for traumatized Holocaust victims, Daniel Shomron, where he fell in love with the catatonic Gabrielle Haller, whom he awoke using his telepathy and became friends with a man calling himself Erik Magnus Lehnsherr, a volunteer. Magnus and Xavier held lengthy debates hypothesizing what would happen if humanity was faced with a new super-powered race of humans, unaware that Magnus himself was a mutant. While Xavier was optimistic, Magnus' experiences in the Holocaust led him to believe that humanity would ultimately oppress the new race of humans, as they had done with other minorities. The two friends revealed their powers to each other when they fought Nazi, Baron von Strucker, and his Hydra agents, who kidnapped Gabrielle because she knew the location of their secret cache of gold. Magnus attempted to kill von Strucker, but Xavier stopped him. Realizing that his and Xavier's views on mutant-human relations were incompatible, Magnus left with the gold. Charles stayed in Israel for some time, but Xavier and Haller were unaware when he left that she was pregnant with his son, who would become the autistic mutant known as Legion, and they separated on good terms.
In a strange town near the Himalayas, Xavier encountered an alien, calling himself Lucifer, the advance scout for an invasion by his race, and foiled his plans. In retaliation, Lucifer dropped a huge stone block on Xavier, crippling his legs. Xavier was freed by Sage, who had heard his telepathic cries for help. Xavier went into a deep depression after loosing the use of his legs and Amelia Voght, a young American nurse, made cheering him up her pet project. Amelia helped Xavier recover during his convalescence in Bombay, India, wherein the two fell in love. While living in an apartment together in Bombay, Amelia found Xavier's notes of a device, called "Cerebro", that could detect mutants. Amelia fought with Xavier, believing that he only wanted her as an experiment, until he used his power to speak in her mind that her loved her. Realizing that he, too, was a mutant, the couple grew very close and Xavier continued his dream with Amelia by his side.
Xavier worked with fellow mutation expert, Dr. Karl Lykos, as well as Dr. Moira MacTaggert, who built a Mutant Research Center on Muir Island, again. Apparently, Charles had gotten over Moira in his travels to the Greek island of Kirinos. Xavier renewed his friendship with Moira, who was now a renowned geneticist, and they began discussing the idea of founding a school for mutants. Xavier discussed his candidates for recruitment to his personal strike force, the X-Men, with Dr. MacTaggert, including those he passed over, which were Kurt Wagner, Piotr Rasputin, Pietro and Wanda Maximoff, and Ororo. Professor Xavier's first student was the 11-year-old Jean Grey, who had been traumatized when she telepathically experienced the emotions of a dying friend. Over the years, Charles made a name for himself as geneticist and psychologist, renowned enough that the Greys were referred to him when no other expert could help their catatonic daughter, Jean. Professor Xavier helped Jean recover and taught her to use her telekinetic powers. Professor Xavier also trained Tessa to spy on Sebastian Shaw and built a machine for Jamie Madrox to learn at home, instead of going to school.
Professor Xavier later met with Fred Duncan, an FBI agent investigating the growing number of mutants. Professor Xavier told Duncan of his plan to locate young mutants and enroll them in his "School for Gifted Youngsters", using his ancestral mansion home as a base to train them to use their powers, as well as provide them conventional educations, for humanity's benefit. The base included subterranean medical labs, a training facility called the "Danger Room", an aircraft hanger with a Stratojet, and Professor Xavier's mutant detection device, code named "Cerebro". Amelia stayed with Professor Xavier, partially because she loved him, but also to convince him to give up his nonsense idea. On the anniversary of his liberation from the Vernichtungslager Extermination Camp, Professor Xavier and Amelia met with Erik, now calling himself Magneto and in costume and helmet designed to shield from telepathy, in Auschwitz, Poland. Professor Xavier pleaded with Magneto that the actions he would set into motion were no different than what the Nazis did to him years earlier, but Magneto laughed and patronized the Professor for claiming to lead mutants, but being confined to a chair. Professor Xavier replied that he may have lost the use of his legs, but not his heart, something Magneto could not say. After both men remind each other that they have the power to destroy each other, Magneto leaves, with Professor Xavier hoping that he saw the error of his ways.
Amelia, then, left Professor Xavier as Scott Summers moved into the mansion, believing the best solution to the "mutant problem" being for mutants to lay low. Professor Xavier tried to force her to stay with his mental powers, but immediately ashamed by this, let her go. Over the following months, Professor Xavier assembled his original team of X-Men: Scott, who took the name Cyclops, Iceman, Angel, Beast, and Jean, who took the name Marvel Girl. A notable menace included Magneto, now a mutant supremacist. They encountered Vanisher, the Blob, the Brotherhood of Evil Mutants, Namor, Unus, and Lucifer. After being controlled, by the Puppet Master, Professor X ordered the X-Men to battle the Fantastic Four, until Beast destroyed his doll and the two teams battled the Awesome Android, who Professor X defeated from afar. They journeyed to the Savage Land and later battled the Juggernaut. Around this time, while the X-Men were battling the Brotherhood of Evil Mutants at Hammer Industries, Magneto and his troops withdrew from battle, after the arrival of a Sentinel. Back at the X-Mansion, the X-Men were approached, by the Evolutionaries, who informed them they were there to ensure the survival of Homo Superior. After a brief battle with the young X-Men, the Evolutionaries sought the help of Magneto and his Brotherhood of Evil Mutants, viewing Magneto as the leader of all mutantkind. After the Brotherhood kidnapped young Emma Frost, Magneto took her to Xavier's School, to use Cerebro. Beast created a device, that shut-off their access to cosmic rays and accidentally killed two of them. When Cyclops vowed to protect mutantkind, the remaining Evolutionary reluctantly left, but not before erasing the memory of their presence from the minds of the X-Men and Brotherhood and vowing to return one day. The X-Men went-on to battle Dr. Bolivar Trask's Sentinels, Mimic, Count Nefaria, the Locust, El Tigre, Puppet Master (when former villain, Mimic, joined the team), the Factor Three, the Super-Adaptoid (when Mimic left the team), The Warlock, Cobalt Man, Mole Man and Tyrannus, Mekano, and Mutant Master.
At this time, Professor Xavier went underground from all of his original students, save Jean, to prepare of the invasion of the alien Z'Nox and had the reformed and dying villain, Changeling, posing as him after giving him a portion of his telepathic power. The X-Men disbanded after Changeling was killed by Grotesk and Professor Xavier left all of his belongings to Scott. Professor Xavier returned with Havok and Lorna Dane to stop the invasion of the Z'Nox, where Prof. Xavier probed every human mind on the planet and was left in a weakened state, and, later, the X-Men survived an encounter with an angry Hulk to help revive him.
Next, Professor Xavier sent the X-Men back to the Savage Land to make sure that Magneto actually perished. After hearing that an old colleague, Professor Hans Jorgenson, had been kidnapped, Professor X summoned the X-Men to track down Spider-Man. After the X-Men defeated him, they returned him to the mansion and learned that Prof. Jorgenson was, actually, kidnapped by Michael Morbius. The X-Men defeated Morbius, saved Prof. Jorgenson, and cured Spider-Man of a toxin. Later, Magneto destroyed the mansion and defeated the X-Men, but a distress call was sent to the Avengers. After capturing the Avengers also, Magneto controlled both groups to kidnap scientists, to create atomic devices that will create him an army of mutants to command. The heroes were saved, after Vision used his powers to take possession of Piper and knocked Magneto unconscious. Later, the X-Men were kidnapped, by the Secret Empire and rescued, by Captain America and Falcon.
New X-Men===Second and Third Team of X-Men=== Years later, when most of his original students were captured by the mutant, island Krakoa, Professor Xavier sent another team comprised of Dr. MacTaggert's students, Kid Vulcan (who was Cyclops' unknown brother), Petra, Darwin, and Sway, all of whom he gave quick, mental combat experience, to rescue them. Professor Xavier also approached Emma, to be the team's telepath, but she refused and the Professor erased the event from her memory. After the team freed Cyclops and Kid Vulcan revealed their connection, the entire team was seemingly killed. Cyclops escaped, but, when he made it back to Professor Xavier, the Professor wiped the traumatizing knowledge, that his new-found brother had died saving him, from Cyclops' memories. Professor Xavier, then, assembled another team of X-Men, including Banshee (former Factor Three operative), Colossus, Nightcrawler, Storm, Sunfire, Thunderbird, and Wolverine to rescue the others on Krakoa, never revealing anything about Dr. MacTaggert's students. The mission was successful and the team stayed together, save Sunfire. Their next mission was Count Nefaria and his Ani-Men, where Thunderbird was killed attempting to stop Count Nefaria's escape. The team went on to battle Kierrok and Professor Xavier was captured by Steven Lang's Sentinels and taken to his space station, until his X-Men rescued him. After, Professor Xavier stayed with a weak Jean in the hospital, after she had piloted the shuttle back to Earth and declared herself the Phoenix. At this time, Professor X had somehow also gained access of a RS-150 Blackbird from S.H.I.E.L.D., as the X-Men's new transportation. Lilandra Neramani, princess of the alien Shi'ar race and the woman he shared an intense psychic bond with across the vast distance that separated their two planets, came to Earth to implore Prof. Xavier for his help against her mad, tyrannical brother, D'Ken Neramani, and he, instantly, aided her by deploying his X-Men. They, then, journeyed to the M'Kraan Crystal’s homeworld to battle the Shi’ar Imperial Guard, where they met Christopher Summers, alias Corsair, Cyclops' father, who had become a space pirate and leader of the Starjammers.
After briefly battling Weapon Alpha, and, later, Warhawk, Phoenix returned from the Savage Land to tell Professor X that all the X-Men were dead. Prof. Xavier shut down the school and traveled with Lilandra to her kingdom, where she was crowned Empress. Prof. Xavier dreamed of her and Lilandra knew they were soul mates. They fell in love and, for a time, Professor Xavier lived on Chandilar, the Shi'ar throneworld, as Lilandra's consort.
Prof. Xavier returned to Earth and resumed his position at the school. Professor X then located Kitty Pryde with Cerebro. Professor Xavier and three of the X-Men, Colossus, Storm, and Wolverine, set out for Deerfield, Illinois to contact her and possibly recruit her as a member of the X-Men. Unknown to Prof. Xavier, the mercenary, Warhawk, had planted a device that enabled his employers in the Inner Circle of the Hellfire Club to monitor Cerebro's activities. The Inner Circle, thus, also learned about Kitty, and one of its leaders, Emma, now the White Queen, also went to contact her. The X-Men then went on to battle the Hellfire Club while attempting to recruit Dazzler. When trying to understand the motives of the Hellfire Club, Angel set-up an invite to a Hellfire Club party, where the Phoenix fell under Mastermind and the Hellfire Club's control and transformed into the Black Queen. After the X-Men battled the Hellfire Club's Inner Circle, Phoenix underwent another transformation into the Dark Phoenix and soared through the universe, where she devoured an entire star and the five billion inhabitants of one of its planets. When Phoenix returned to Earth, she threatened to kill everyone, but Professor X was able to keep Phoenix under control and helped her will herself back to normal. The X-Men were then teleported away by the Shi'ar. The Shi'ar Empire had witnessed Dark Phoenix consuming the star and Prof. Xavier had no other choice but to challenge the Shi'ar Imperial Guard to a duel over the fate of the Phoenix. The battle triggered her transformation into Dark Phoenix once more and she understood that she would never be able to fully control the dark hunger inside and sacrificed herself on moon. Jean Grey was believed dead.
On Nightcrawler’s twenty-first birthday, Margali Szardos transported Kurt’s soul to a simulacrum of Dante’s hell and Professor X called Dr. Strange and sent the X-Men to his rescue. Then, the X-Men stopped the attempted assassination of Senator Robert Kelly by the Brotherhood of Evil Mutants and, shortly thereafter, registered an anomaly on Cerebro and sent the X-Men to investigate James Marks, the product of cross-breeding between an Earth woman and a Dire Wraith. Later, a woman known as Miss Locke kidnapped many of the X-Men's loved ones, to use as hostages in order to force the X-Men to aid her in freeing her employer, Arcade, from captivity by one of Doctor Doom's robots. Prof. Xavier called-in the aid of Havok, Polaris, Iceman, and Banshee to assist. Next, the X-Men battled Garokk, Magneto, and after Storm sensed that Arkon the Imperion was in danger, the X-Men and the Fantastic Four aided him in battling the Badoon. Later, Professor Xavier was contacted, by Spider-Woman, stating that she had found the comatose body of Carol Danvers (Ms. Marvel) and, after probing her mind, the professor found that Rogue was the culprit. After stating her disapproval with the Avengers, Professor Xavier allowed Carol to stay at the mansion, until she was healed. The team went on to battle the Sentinels and during a coupe, first met the alien Brood and battled Deathbird and Admiral Samedar to restore Lilandra to the Shi'ar throne, where Prof. Xavier was sent into a coma. Unknown to anyone, Professor X had been implanted with a Brood Queen egg at the time. Professor X woke from his coma to learn that his X-Men and Lilandra had left him and the only one in the mansion was Illyana Rasputin, Colossus' younger sister, somehow, now a teenager. Around this time, Professor X aided Spider-Man in battling Mentallo and was unable to rebuild Anthony Power's son, Matthew's, comatose mind. Professor Xavier was able to help Dr. Lykos, who had been trapped as Sauron. Professor X found that Dr. Lykos was infected with a genetic virus that mutated him and isolated the alien element in his DNA matrix, which cured him.