Jon Snow is raised as a Stark child, but his actual parentage is unknown. He is said to appear more "Stark-like" than any of his half brothers, with a lean build, dark hair, and dark gray eyes. He is graceful and quick, a skilled horseman and a gifted swordsmen. Jon's illegitimate status made him bitter, with a desire to prove himself and grow up faster than his siblings, and drove him to join the Night's Watch to earn his own honor. Although Jon learns to fit in with The Watch, he is conflicted about separating from his old life. After his father's execution, Jon attempts to desert The Watch, but his friends bring him back and he fully commits to The Black.
When Jon was fourteen years old, he was on his way home to Winterfell with the men of his family, and they stumbled upon a litter of five direwolf pups. Jon convinces his father to let each of the five legitimate Stark children each keep a pup, since the direworf is the Stark house sigil, it's meant to be. Jon discovers a sixth albino direwolf pup, outcast from its siblings, which Jon claims for his own and names "Ghost." Ghost is never too far from Jon's side throughout the story.
There is so much more to this character, but will stop here to avoid any further spoilers!