Josh Corrigan is the younger brother and ward to Atlas who has all legal rights and full custody of him. He is best friends with Theo.
Josh was a homeless 12-year-old when he and Atlas met. The two didn't have a relationship for the first 12 years of his life, since Atlas never knew of his long-lost brother. Atlas deeply cares about Josh, and Josh looks up to him as a father figure and his only real family. At the end of It Starts With Us, Josh is officially living with Atlas; becoming his legal guardian and father figure.
He grew up in a cold, abusive home with his mother, Sutton and had no relationship whatsoever with his father, Tim. Josh ran away from home; becoming homeless when determined to find his father. However, ends up forming a bond with his long-lost brother; moving in with him.