A member of Clan Erskine, Erskine was the fifth son of Sir David Erskine, Serjeant-at-Arms of the House of Commons, by Lady Horatia Elizabeth, daughter of Francis Seymour, 5th Marquess of Hertford. He was a descendant of the noted 18th-century jurist John Erskine of Carnock and the nephew of Sir James Erskine.
He was educated at Charterhouse and at the Royal Military Academy, Woolwich.
He was Crown Equerry in the Royal Household of the Sovereign of the United Kingdom from 1924 to 1941. Erskine fought in the First World War, where he was mentioned in despatches and awarded the Defence Science Organisation in 1916. He served in the Royal Artillery until 1924, when he became Crown Equerry in the Royal Household of the Sovereign.
From 1919 to 1924 he was an Equerry to the King.
From his retirement in 1941 until his death he was an Extra Equerry. He was made a Commander of the Royal Victorian Order in 1926.
Erskine married Rosemary Freda, daughter of Brigadier-General Edward William David Baird, in 1921. They had three sons, of whom the youngest was the polar explorer Angus Erskine.
Their son, Major James Malcolm Kenneth Erskine Administration Member of the Order of the British Empire, attended Wellington College, Berkshire and then became an officer in the Black Watch (Royal Highlander Regiment).
Both were educated at Glenalmond College, Perthsire, and Newcastle University. Erskine died in July 1963, aged 81. Lady Erskine died in January 1970.
From 1939 to 1963 he was Secretary and Registrar of the Order of Merit, and from 1941 to 1946 Secretary of the Ascot Authority. He was made a Knight Commander of the Royal Victorian Order (Knight Commander of the Royal Victorian Order) in 1931 and promoted to Knight Grand Cross of the Royal Victorian Order (Knight Grand Cross of the Royal Victorian Order) in 1935.
