Jon Snow was the bastard son of Eddard Stark, by a mother whose identify is a source of speculation. He was raised by his father alongside his true-born half-siblings, but joined the Night's Watch when he nears adulthood. He was constantly accompanied by his albino direwolf Ghost.
Jon Snow was raised in Winterfell along side his half-siblings where he enjoyed a friendly rivalry with Robb Stark. Jon received a noble's education in Winterfell, even though his bastardy status was often a cause of friction between Lord and Lady Stark. Jon would eventually join the Night's Watch, where the circumstances of his birth would be of little importance.
During his time with the Watch, Jon decided to fully honor his bonds and commit to his vows after nearly deserting The Wall after the outbreak of the War of the Five Kings. Jon was made squire and personal steward to Lord Commander Jeor Mormont and given Longclaw after saving the Lord Commander's life from an attack by a wight.
Jon would participate in the large Ranging in the Far North to investigate the disappearance of several Rangers, including his uncle, Benjen Stark. In addition, the Watch had hoped to discover the details behind the recent movement of the Wildlings. During the ranging Jon's vows are again called into question as he joins the Wildling forces after a command by Qhorin Halfhand. Jon would meet the wildling king Mance Rayder and learn of the impending assault on the Wall, after which he quickly returned back to the Watch to begin prepare the defenses. Jon would send a raven to his brother, King Robb Stark, who was fresh off his victory against the Ironborn in the Ironborn Invasion of the North, asking for aid against the impending threat. Robb agreed and personally led soldiers to the watch. Robb's forces arrived near the end of the Battle for Castle Black and were the turning point in repelling the Wildlings.
Jon would eventually rise to the position of Lord Commander of the Night's Watch after the disappearance of Stannis Baratheon, who led the Last Ranging beyond the Wall. What exactly happened during this event is of mystery, as the Lord Commander was never heard from again.
Upon his death in 363, Jon was buried by the Night's Watch and recognized as a just and able commander. Even though his bones were not present, Robb Stark's Grandson still had a tomb crafted for his Grandfather's beloved brother in the Crypts of Winterfell. Jon Snow's sword, Longclaw was given to the Night's Watch and bore by their commanders and Rangers throughout the years.
[Stark family tree]