Born in Brentford, Henderson was the eldest son of Alexander Henderson, 1st Baron Faringdon of Buscot Park in Berkshire (now Oxfordshire), and his wife Jane Ellen (née Davis). He served in the Royal Berkshire Regiment of the British Army, and later joined the Territorial Army in the Berkshire Yeomanry. He sat as Member of Parliament for Abingdon from 1910 to 1916. Henderson resigned his seat on his appointment as military secretary to the Duke of Devonshire who was to become Governor General of Canada in November 1916.
Henderson married Lady Violet Charlotte, daughter of Robert Dalzell, 11th Earl of Carnwath, in 1901. They lived at Kitmore House at Shellingford in Berkshire (now Oxfordshire). He died in November 1922, aged 47 in Faringdon, twelve years before the death of his father. He had four children and his eldest son, Alexander Gavin, succeeded in the barony in 1934.
- The London Gazette: . 2 March 1894. Retrieved 14 July 2008.
- The London Gazette: . 25 August 1908. Retrieved 14 July 2008.
- "News in Brief" (News in Brief). The Times (London). Wednesday, 30 August 1916. (41259), col G, p. 3.
- Ford, David Nash (2008). "History of Shellingford, Berkshire (Oxfordshire)". Royal Berkshire History. Nash Ford Publishing. Retrieved 3 June 2011.
- Leigh Rayment's Historical List of MPs [self-published source][better source needed]
- Lundy, Darryl. "FAQ". The Peerage.[unreliable source]
- Hansard 1803–2005: contributions in Parliament by Harold Henderson
|Parliament of the United Kingdom|
Edward Anthony Strauss
|Member of Parliament for Abingdon
Archie Kirkman Loyd