Jack is the protagonist and hero of the story. He is brave and has an inner strength that even Ŗeżżőcħ seems to notice. Jack is devoted to his friends and fiercely loyal; he is constantly Putting Friends First and endangering his own life to keep his loved ones safe. Jack is also sarcastic, witty, and filled with an endless supply of jokes. He refers to pop culture and describes how growing up in foster care meant that fictional icons influenced his personality more than anyone he lived with. Because Jack grew up without parents, he is now deeply attached to his friends and the life they have built. At the beginning of the narrative, he selfishly wants to keep his friends to himself. His challenge is to overcome The Fear of Being Alone.

When the kids find the radio and hear proof that other human beings are alive, everything starts to change. Jack fears that if his friends find their families, they will leave him behind. Ŗeżżőcħ plays on this fear by showing Jack a vision of his future self, roaming a deserted world with Rover and without human company.