McMaster was born into a wealthy South Carolina family who owned many slaves before the American Civil War.[1] His father John was also a politician.[2]
↑McMaster, Fitz Hugh (1926). The History of MacMaster—McMaster Family. Allen County Public Library Genealogy Center. Columbia, South Carolina: The State Company. pp. 121, 126. At the breaking out of the Confederate War John McMaster owned about twenty-five slaves, several small farms, and several houses and lots in the town of Winnsboro. He was worth at this time about $40,000. […] James Riley McMaster, M. D. Born Winnsboro, Feb. 21, 1822; died Aug. 20, 1894; married Harriet Mobley, 1854; practiced medicine and was large planter and slave owner before Confederate War