Black was born in Kensington on 8 April 1902, one of the six children of Robert Wilson Black (1871–1951) and his wife Annie Louise ("née" North). He was educated at King's College School. He qualified as a chartered surveyor and became a successful property developer, making himself a millionaire before he reached the age of forty. In 1930 he married Dorothy Joyce, daughter of Thomas Birkett, of Wigston Hall, Leicester. They had one son and two daughters. Black was grandfather to Andrew Black, the gambling entrepreneur, founder of Betfair.