Howse was born in Somerset, England, and followed his father into the medical profession. He immigrated to Australia in 1889 and eventually settled in Orange, New South Wales. During the Boer War, Howse served with the Australian medical corps. He was awarded the VC for his rescue of a wounded man at Vredefort in July 1900, while under heavy rifle fire. During the First World War, Howse served in New Guinea, Gallipoli, and on the Western Front. He oversaw the medical services of the Australian Imperial Force (AIF) and finished the war with the rank of major-general. He was elected to parliament in 1922, and was subsequently appointed to cabinet by Stanley Bruce. He served as Minister for Defence (1925–1927), Health (1925–1927; 1928–1929), and Home and Territories (1928).