Originally Posted by munchausen
EDIT: Jorah, not Joreth.
Even in the HBO production, it is noted he is the son of the current Lord of the Night Watch, and that he fled the King's justice due to selling some criminals marked to join the Night Watch. Also, here's a minor spoiler:Warning: Spoiler! (Click to show)
There's really no need to develop his character much past this point. He'll be gone by the middle of S2.