Beresford joined the 7th Hussars as a Second lieutenant in February 1887, was promoted to Lieutenant on 10 April 1889, and to Captain on 7 October 1896. He saw military service mainly in Africa, first during the Second Matabele War in 1896 and later during the Second Boer War. In January 1900 he was seconded to the Staff, and appointed an Aide-de-camp to the Duke of Connaught, Commander-in-Chief of Ireland. In early February 1902, he was appointed in command of the 37th Battalion, Imperial Yeomanry, with the temporary rank of lieutenant-colonel, and the following May left Aldershot with his Battalion for service in South Africa. From 1903 to 1904 he served in Somaliland.