Harold Greenwood was the grandson of Sir Henri-Gustave Joly de Lotbinière, Premier of Québec. He attended the Royal Military College in Kingston, Ontario from which he graduated in 1914. In World War I, he came to Europe and later represented Great Britain at the 1928 Winter Olympics. In the 1940s he served as a brigadier-general in the Corps of Royal Engineers in India, Ceylon (now Sri Lanka) and Southeast Asia. In 1945 Greenwood was commissioned as Chief Engineer to the Western Command, and he retired shortly thereafter, in 1947. For his services he was appointed Commander of the Order of the British Empire (CBE).