Charles' telepathic powers began emerging when he was still a boy, around ten, and, as he grew older, he learned to control them. Due to the immense psychic energies emanating from Charles' head, he became bald at a young age. With his powers, Charles discovered that Dr. Marko married to his mother for her money, admitting that he was jealous of Dr. Xavier's wealth. Realizing Dr. Marko did not have feelings for Sharon, she started drinking, becoming an alcoholic. Marko started to abuse both Sharon and Cain, and Charles linked his mind to both of them. He telepathically linked to his mother's in an effort to share the abuse with her and alleviate it. On another occasion, he found himself experiencing the anguished thoughts and emotions of Cain, after Cain had been beaten by his father. Feeling Cain's pain aggravated Cain's dislike to Charles, but the inexperienced young Charles could not control or end his contact with Cain's mind at this time. Sharon died shortly thereafter of a broken heart, leaving Charles to live with his stepfather and abusive stepbrother.

 Meeting Moira

 Xavier was a brilliant student, attending multiple schools throughout his educational career. He attended Bard College in his early teens and graduated from Harvard University when he was 16 years old. Intent on undertaking graduate studies, Xavier entered England's Oxford University to gain his Ph.D.s Genetics, Biophysics.

 Xavier was approached by Moira Kinross during a fair in Oxford, asking him why he was smiling. He simply responded that recently, he had the "most wonderful dream", referring to his ideals of the peaceful coexistence between humans and mutants. Charles questioned Moira whether they have ever met before, which Moira responded to by asking him to read her mind, showing him all the lives she had already lived, a consequence of her mutant powers. Professor X was completely crushed by the experience, left thunderstruck by the revelation that no matter what would have happen, mutantkind would always lose. In her tenth and tentatively last life-cycle, all she ever wanted was for Professor X and Magneto to work together, avoiding mutants always losing as she saw in her past timelines. After Xavier's first encounter with Moira, he joined her in a long-term plan to guarantee the future of mutantkind. Eventually, he and Moira fell in love, as it has happened in some of Moira's previous lives. Their passionate discussions on genetic mutation gave way to an equally passionate romance.

 Meanwhile, Marko continued to live at the mansion. Marko grew increasingly resentful of his step-brother's scholastic and athletic achievements, as well as his telepathic powers. Marko even pushed Xavier too far one day and the two got into a fight, which Xavier easily won. While still studying at Oxford he was confronted on campus by two mutants named Logan and Victor Creed who, upon learning that the US government was actively imprisoning mutants, were seeking to band mutants together in a common group. Xavier flat out turned Logan and Creed down, something he grew to regret in later years. It had also been hinted that Mister Sinister interfered with Moira and Xavier's relationship, as he was posing as a professor at Oxford at the time. Xavier and Moira planned to be married, but after finishing his work at Oxford, Xavier was drafted.

 Having been drafted, Xavier was sent to Korea during the Korean War. There, Xavier and Marko served in the same unit. Attempting to bring back the deserting Marko, Xavier witnessed Cain's discovery of a 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".

 Dangerous Mutants

 Xavier became deeply depressed after Moira broke off their engagement with no explanation. After inheriting his family's considerable wealth, Xavier began traveling abroad. After leaving the army, Xavier discovered that Moira had 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 host, the first evil mutant he had ever met. After defeating Farouk, Xavier realized how deadly mutant powers could be in the wrong hands. This made Xavier find his life dream, he decided to bring mankind and its mutant children together in peace and harmony, aiming to protect humanity from evil mutants and 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.

 Erik Lehnsherr

 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. He also became friends with a man calling himself Erik Magnus Lehnsherr, a volunteer. Magnus and Xavier held 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. Xavier stayed in Israel for some time before he and Haller separated on good terms. They were unaware when he left that she was pregnant with his son, who would become the autistic mutant known as Legion.

 Crippled

 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. Unfortunately, the rock had permanently damaged his legs, rendering them unusable. Xavier went into a deep depression after losing 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, stopping only when he used his power to speak to her telepathically, telling her that he 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 old flame Dr. Moira MacTaggert, who had built a Mutant Research Center on Muir Island. 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, Xavier 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.

 X-Men

 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 wearing a 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. After both men reminded each other that they had the power to destroy one another, Magneto left, with Professor Xavier hoping that he saw the error of his ways.

 

Xavier and his first students

 Amelia 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. The first menace they would face was Xavier's old friend Magneto, now a mutant supremacist and his Brotherhood of Evil Mutants.

 After training them for several years, Professor Xavier went underground from all of his original students, save Jean, to prepare for the invasion of the alien Z'Nox and had the reformed and dying villain, Changeling, pose 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. Prof. Xavier probed every human mind on the planet and was left in a weakened state, but was revived using a device created by Bruce Banner.^[34]