Jon Snow is the natural son of Lord Eddard Stark of Winterfell, born in 283 AC during Robert's Rebellion and brought home by his father at the close of the war. The identity of his mother Eddard never revealed: some name the wet nurse Wylla of Starfall, others the lady Ashara Dayne, and still others a fisherman's daughter of the Three Sisters, but to the end of his days Lord Eddard refused to speak of her. He has the long face and grey eyes of the Starks, more a Stark in his looks than any of his trueborn half-siblings, and grew up solemn, guarded, and quick to feel a slight, ever conscious of the stain of his birth. Raised at Winterfell beside Robb, Sansa, Arya, Bran, and Rickon, taught his letters by Maester Luwin and the sword by the master-at-arms Ser Rodrik Cassel, he was closest to Robb, who was near his own age, and to Arya, who shared his outsider's heart; Lady Catelyn never warmed to the bastard her husband had set among her children. When Eddard's party found a litter of direwolf pups in the late summer snows, it was Jon who saw there was one for each Stark child and, after, an albino runt cast apart for himself, the silent wolf he named Ghost.
When King Robert came to Winterfell and named Eddard his Hand, Jon, who could not be settled in the world as a bastard, begged leave of his uncle Benjen, the First Ranger, to take the black, and rode north to the Wall at fourteen. He gave Arya the slender blade Needle in parting and went believing the Night's Watch a brotherhood of honor. At Castle Black he found instead old men and thieves, and the spite of the master-at-arms Ser Alliser Thorne, yet he made himself a leader among the green recruits and a true friend to the craven, kindly Samwell Tarly, whom he shielded from the bullies of the yard. Appointed personal steward to Lord Commander Jeor Mormont, Jon chafed until he understood the post was meant to groom him for command. When a dead ranger rose as a wight and attacked the Old Bear, Jon burned the creature and saved his life, and Mormont rewarded him with the Valyrian steel bastard sword Longclaw, its pommel recast as a white wolf's head. News of his father's execution and his brother Robb's war drove him to desert for the south, but his sworn brothers rode him down and brought him back, and he chose at last to keep his vows.
Jon marched with the great ranging beyond the Wall to seek out the gathering wildlings, and was given over to the scout Qhorin Halfhand. Trapped by the free folk in the Skirling Pass, Qhorin commanded Jon to feign desertion, join the enemy, and learn their plans, then forced his own death at Jon's hand to make the deception true. So Jon came among the wildlings as a turncloak, fell in love with the spearwife Ygritte, and climbed the Wall at the side of the raiders, until duty drove him to slip away and warn the Watch of Mance Rayder's host. Wounded in his flight, he reached Castle Black to help hold the Wall through the wildling assault, in which Ygritte died in his arms. He led the defense after the death of Donal Noye, then crossed the field under a flag of truce to treat with Mance, and was saved only by the sudden arrival of Stannis Baratheon's host. Though Stannis offered to legitimize him as Lord of Winterfell, the prize Jon had always secretly wished for, he refused it, and soon learned that, through the efforts of Samwell Tarly, he had been chosen the 998th Lord Commander of the Night's Watch, the youngest in living memory.
As Lord Commander, Jon ruled a Wall caught between Stannis's demands, the red sorceries of Melisandre, and a Night's Watch that mistrusted his sympathy for the free folk. He beheaded the disobedient Janos Slynt with Longclaw in his father's fashion, garrisoned the empty castles, and against bitter objection brought wildlings south of the Wall to swell the Watch and stand against the Others, the true enemy of the cold nights to come. He sent Samwell, Maester Aemon, and Gilly to the Citadel, and smuggled Mance Rayder's infant son to safety in their charge. When a letter came from Ramsay Bolton boasting of Stannis's defeat and demanding his hostages, Jon broke faith with his vows at last: he called the free folk to the Shieldhall and announced he would ride south against the Boltons. For that choice his own officers turned on him, and in the yard of Castle Black, Bowen Marsh and other sworn brothers fell upon him with knives, each murmuring "For the Watch," and left him bleeding in the snow at the close of A Dance with Dragons.