His parents were both convicted criminals and he spent his first 14 years as a foster child in a large family of farm laborers (10 children), the Morrises, who worked for a leading National Party MP, who became Banks' mentor. He then lived with his birth parents for two years, but was sent to boarding school when they were again sent to prison.
He has had contact with his birth sister, but that has stopped.
He also has had a career as a restaurateur (and is the former chairman of the New Zealand Licensed Restaurant and Cabaret Association) and property developer, and he is a licensed pilot. He and his wife adopted three Russian children in 1995.