Harold Singleton was born to Harry Middleton Singleton (1871 - 1944) and his wife, schoolteacher Mary Leighton Nance (1873 - 1934) at his grandparents' home in Boonsboro, Bedford County, Virginia (later annexed to Lynchburg) on August 19, 1906.
He married Catherine Cecilia Lacy (1915 - 1967).