Julio Castillo was born in New Orleans, Louisiana in 1970. He is of Latin American descent, his mother from Honduras and his father from Nicaragua. He was an accomplished high school athlete and received a partial scholarship to college as a result. He played semi-pro football with the New Orleans Sharks for a year, and serves as a football referee. He has been married since 1996 and has two children. His wife is a screenwriter and the author of the mystery novels Gumbo Justice and Jambalaya Justice, both of which feature the character Big Who, based upon Julio. He lives in New Orleans, "Hollywood South," with his family, two dogs, deaf cat, and guinea pig.