In 1960, Sokolov participated in the Soviet Vostok program, designing the multi-motor cluster for the Vostok A-1. He wanted to keep investigating for the Soviet space program, but, instead, he was named the Chief Designer of the Secret Weapons Research Office for the Soviet Union. In 1961, he began designing the Shagohod and it's intermediate range nuclear weapons capabilities. He began to worry about the weapon he was developing and it's consequences on the world. He decided to defect with his family from the Soviet Union. In 1962, Major Zero helped Sokolov and his family defect to the U.S., but in late October, the Cuban Missle Crisis threatened the world with a nuclear holocaust. On October 28, America and the Soviet Union reached a compromise. The Soviet Union agreed to remove its missiles from Cuba. But in exchange the Americans had to surrender Sokolov over to the Russians. He was then placed in an abandoned research facility near the OKB-812, and was guarded by KGB soldiers to make him work on the Shagohod. Sokolov showed fear to his enemies but also presented courage, when Tatyana was being electrocuted by Colonel Volgin, Sokolov threatened that he would not work on the project if she is hurt, but was proven wrong when Colonel Volgin threatened him. He has no shame for what he does but has guilt that his gifts are being used to bring destruction to mankind. He loves his family and shows affection towards people who are being hurt by others.
» Operation Snake Eater After Naked Snake succeeded in rescuing Sokolov, he was quickly confronted by The Boss, who told Snake of her defection. The Boss then took Sokolov as a "gift" for Volgin. They also took Tatyana, also known as EVA, who was supposedly Sokolov's lover. One week later, Tatyana requested the battle data of the Shagohod from him. Sokolov gave it to her, thinking it would be handed over to Khrushchev - unbeknownst to him, it would actually be given to the People's Republic of China. Snake attempted to rescue him again, but he informed Snake that he was too late, as the Shagohod had already been finished. Snake contradicted him, saying that if the liquid fuel tanks were to be destroyed along with the Shagohod, there would still be hope for the safety of the world. Just when Snake was going to see him out of Groznyj Grad, Sokolov refused, as he would probably sent to a Soviet prison camp, as Khrushchev had abandoned him. Snake asked him about returning to America, but Sokolov told him that he'd only be used for America's nuclear purposes, and instead of being taken anywhere he'd rather just be ensured to be safe. After the Shagohod was complete and Colonel Volgin felt that Sokolov had served his purpose, he was beaten to a pulp and placed in a Soviet prison camp. Snake's head had been covered in a bag during Sokolov's beating, so Snake assumed the worst, that Volgin had brutally murdered him with his bare hands. Sokolov actually survived with the help of a Fake Death Pill given to him by the CIA, and The Boss helped him escape Groznyj Grad. He was later captured by the KGB.
» San Hieronymo Takeover While imprisoned, the camp was secretly infiltrated by Gene of the FOX unit, who rescued Sokolov and succeeded in bringing him back to the United States and reuniting him with his family. While in the United States, Sokolov's previous assumptions came true, and he was recruited by Gene to design and build the first official Metal Gear project, based on a heavily modified version of the blueprints in Granin's office. Gene brought him to the San Hieronymo Peninsula to build Metal Gear RAXA and the ICBMG, while Sokolov secretly planned to rebel against Gene, who he had realized as a maniac. When Naked Snake, now known as Big Boss, was captured by the remaining members of FOX, Sokolov saw his opportunity to rebel. After Big Boss escaped and began looking for ways to stop Gene's rebellion, Sokolov contacted him under the name "Prividyenie," (Ghost in English). Ghost thanked Snake for taking care of Volgin six years prior, during the events of Operation Snake Eater. After Big Boss destroyed RAXA, Sokolov emerged from the shadows and told him that RAXA was only a test model. Later, when Big Boss attempted to disable the ICBMG, Sokolov assisted him, telling where it's armor was at it's weakest. After the mission, Sokolov was presumably reunited with his family and retired from rocket science, for the better of the world.