Jon Snow, born Aegon Targaryen, is the son of Lyanna Stark and Rhaegar Targaryen, the late Prince of Dragonstone. From infancy, Jon is presented as the bastard son of Lord Eddard Stark, Lyanna’s brother, and raised alongside Eddard’s lawful children at Winterfell. Jon’s true parentage is kept secret from everyone, including Jon himself, in order to protect him from those that sought the complete annihilation of House Targaryen.
Jon joins the Night’s Watch and is later elected as Lord Commander. As a result of several controversial decisions, such as allowing the wildlings to settle south of the Wall, Jon is murdered in a mutiny, but is resurrected by Melisandre.
Freed from his Night’s Watch vows, Jon and his half-sister Sansa Stark retake Winterfell from House Bolton, restoring House Stark’s dominion over the North. Jon is declared King in the North.