Jay McNally is the 11-year-old brother of Lou McNally. He lived in another foster home while Lou lived with the Papadakises. His father died and his mother left when Lou was only a baby.
He is wiry and strong with freckles & looks a lot like Lou. He has a reserved nature. He & Lou go to live with their aunt & uncle. In Book 116, the McNallys move to Stoneybrook. Jay thinks he doesn't need a babysitter. Abby agrees to let him be a " helper". Jay is really close to Lou and is really happy.