Jack is a young boy. He is bookish, careful and thoughtful, but he is NOT a nerd! Jack has tremendous curiosity about the world around him and loves to take notes about his observations. Jack tends to be very cautious in new situations, and his adventures in the tree house help him develop his confidence. He has a good (and protective) relationship with his younger sister, Annie, though her more impetuous nature often gets on his nerves. This is a big role and requires a strong singer and actor.