Dugdale was born in 1877, the youngest son of Colonel James Dugdale, of Sezincot, Moreton in the Marsh, Gloucestershire. He was commissioned into the British Army as a second-lieutenant in the 5th Lancers in October 1899. The outbreak of the Second Boer War the same month saw the regiment sent to South Africa, where they took part in the Ladysmith Relief Column. He was promoted to the rank of lieutenant in May 1900.