On September 13, 1876, Sullivan married Helen M. Bliss in San Francisco, and they had five children. She died December 30, 1918. Sullivan died at his home on January 23, 1928. A grandson, Robert P. Sullivan, was a graduate of the University of California, Hastings College of the Law (class of 1936), and a San Francisco County Superior Court judge from 1961 to 1971.
