A direct descendant of John Scandrett Harford of Blaise Castle, he was educated at Repton School and Balliol College, Oxford. Between school and university he enlisted as a second lieutenant in 2nd Battalion Essex Regiment and saw action in France between 1917 and 1918. After a period as a schoolmaster at Eton College from 1922 to 1926, Harford joined the Colonial Administration Service and was posted to Nigeria (1926–1934).
He was subsequently appointed:
- Administrator of Antigua and Federal Secretary of the Leeward Islands (1936–1940);
- Administrator of Saint Kitts and Nevis (1940–1946);
- Acting Governor of the Leeward Islands (various periods between 1937 and 1946);
- Companion of the Order of St Michael and St George (1943);
- To serve in the Colonial Office (1946–1947);
- Colonial Secretary of Mauritius (1948–1953);
- Acting Governor of Mauritius (1948 and 1950);
- Governor and Commander-in-Chief of Saint Helena (1954–1958);
- Knight Commander of the Order of the British Empire (1956).
He was married twice:
- (14 March 1932) to Countess Thelma Alberta Louisa Evelyne Metaxà (died 22 October 1934), sister of 9th Count Metaxà, and only daughter of Count Andrea Francis Albert Cochrane Metaxà RNR; 1 son.
- (20 February 1937) to Lilias Madeline (died 9 December 2006), eldest daughter of Major Archibald Campbell AEC; 2 daughters.
- "Metaxà". Burke's Genealogical and Heraldic History of the Peerage, Baronetage and Knightage: Privy Council and Order of Precedence (96th (Coronation honours) ed.). London: Shaw Publishing in conjunction with Burke's Peerage. 1938. pp. 2689–2690.
- Peter Townend, ed. (1965). "Harford of Horton". Burke's Genealogical and Heraldic History of the Landed Gentry (18th ed.). London: Burke's Peerage. Vol. I, pp. 367–370.
- Peter Townend, ed. (1972). "Campbell, formerly of Auchendarroch and Inverawe". Burke's Genealogical and Heraldic History of the Landed Gentry (18th ed.). London: Burke's Peerage. Vol. III, pp. 140–141.
- John Jones and Catherine Willbery (Edd.), ed. (1993). The Balliol College Register (1940–1990) (6th ed.). printed for private circulation.
Hubert Eugène Bader
| Administrator of Antigua
Douglas Roy Stewart
| Administrator of Saint Christopher-Nevis-Anguilla
Leslie Stuart Greening
| Governor and Commander-in-Chief
of Saint Helena
Robert Edmund Alford