Morris served in the army from 1915 to 1934. After serving in the trenches during the First World War, he transferred to the Indian Army's 3rd Gurkha Rifles. He took part in two attempts to climb Mount Everest; the first under General Charles Granville Bruce and climbing leader Lt-Col Edward Lisle Strutt in 1924, and the second in 1936 under Hugh Ruttledge. On the latter, his personal servant was Tenzing Norgay, who made the first ascent of Mount Everest with Edmund Hillary in 1953.