Butler joined the 3rd Battalion, the Northumberland Fusiliers in 1897. He was commissioned into the Royal Warwickshire Regiment as a 2nd Lieutenant on 20 May 1899. He was promoted to the rank of Lieutenant on 1 April 1900 and fought in the Second Boer War of 1899–1901 from where he was invalided with malaria and typhoid having taken part in the advance to Pretoria and operations in the Koomati Valley. He served with the King's African Rifles between August 1905 and April 1908, during which time he was posted in East Africa and explored northern Arabia disguised as a Bedouin and drew up the first map of the route from Baghdad to Damascus. When he returned his transferred to the South Staffordshire Regiment, before being employed with the Egyptian Army between April 1909 and May 1915, he was promoted to Captain on 18 January 1908 and involved in operations in Southern Kordofan in Sudan in 1910. During World War I, Butler served with the Egyptian Expeditionary Force from November 1914 until May 1915, when he was posted to Gallipoli. In January 1916, he returned to serve with the EEF for two months, before being transferred with the ANZAC Corps to France and Belgium in March 1916; he remained there until the end of the War. He was wounded and mentioned in despatches four times; he received the Distinguished Service Order, the French Croix de Guerre and the Order of the Sacred Treasure, and was appointed a Commander of the Order of St Michael and St George. Butler was also promoted to the rank of Major on 12 August 1915 and made a brevetLieutenant-Colonel in June 1918; he served as a General staff Officer for much of the war, beginning with an appointment in the 3rd Division in the Mediterranean Expeditionary Force as GSO2 on the staff of General Birdwood who commanded the ANZAC Corps. After several months in the 2nd division with the MEF, he was posted to an equivalent position in France in February 1916, which lasted until January 1918, when he was promoted to the 1st Division; he remained there until March 1919. From June 1919 to August 1920, Butler was a General Staff Officer in Constantinople. In October 1920, he was appointed Assistant Military Secretary to the General Officer Commanding the Northern Command in India and served in Waziristan. He relinquished his post on 11 August 1923 and was posted as Military attaché in Bucharest the following month, serving until April 1926. Promotion to Colonel followed in November 1925, with seniority from June 1922. Between October 1926 and April 1930, Butler was Inspector-General of the Royal West African Frontier Force and on 28 March 1930 was appointed a Brigadier Commanding Troops and Commandant in the Sudan Defence Force with the rank of temporary brigadier up to 16 July 1934, when he was promoted to Major-General. He then command the 48th Division of the Territorial Army between 1935 and 1939, and was appointed a Companion of the Order of the Bath in 1936. Butler retired in 1939, but was re-employed on the outbreak of World War II. He was Head of the Military Mission to Turkey between 1939 and 1940 and liaison in Africa, before serving as Head of the Military Mission to Ethiopia until 1943. He died on 16 July 1964 and his home in Hambledon, Hampshire.
