[2] He was educated at Harrow School, followed by the Royal Military College, Sandhurst, from where he graduated and was commissioned into the Scots Guards.
Upon the outbreak of World War II, he served as the first Commanding Officer of the 7th Battalion, King's Own Scottish Borderers.
[3] On 14 October 1924, he married American heiress Philippa Fendall Wendell at St Margaret's, Westminster.
Philippa was the sister of Anne Catherine Tredick Wendell, first wife of Henry Herbert, 6th Earl of Carnarvon.
On his death, the earldom and other titles passed to Randolph's second cousin once removed, Andrew Clyde Stewart, a great-great-grandson of the 9th Earl.