Simon was a resident of Harding Township, New Jersey. Simon married his first wife, Carol Girard Simon in 1950. william and Carol Simon had two sons and five daughters (Bill Simon, J. Peter Simon, Mary Beth, Carol Leigh, Aimee, Julie Ann, and Johanna Simon) and twenty-seven grandchildren. She died in 1995. Simon married his second wife, Tonia Adams Donnelley in 1996.