Robin Douglas-Home was the eldest son of the Honourable Henry Douglas-Home from his first marriage to Lady Margaret Spencer. His uncle was the former British Prime Minister Sir Alec Douglas-Home and his younger brother Charles Douglas-Home who was editor of The Times.
Douglas-Home was a jazz pianist and a leading society figure during the 1950s and 1960s. In the 1950s he had a relationship with Princess Margaretha of Sweden but according to the press they were refused permission to marry by her mother, Princess Sibylla, notwithstanding a subsequent statement from King Gustaf VI Adolf saying, "The King has not imposed any ban on the marriage in question". However, Princess Margaretha's nanny and confidante Ingrid Björnberg states categorically in her memoirs that the breakup of the couple was not due to Princess Sibylla refusing to permit them to marry, but because Princess Margaretha did not wish to marry him.
Douglas-Home married the fashion model Sandra Paul in 1959 and they had a son in 1962, Sholto. The couple were divorced in 1965 coinciding with his romance with Princess Margaret, Countess of Snowdon. His divorce was the subject of a BBC television documentary by Alan Whicker.
Douglas-Home was author of an authorised biography of Frank Sinatra (1962) and published four novels, including Hot for Certainties (1964) which won the Author's Club First Novel Award. He also wrote a number of articles for journals and magazines such as Queen and Woman's Own.