Smith was commissioned into the Essex Regiment in November 1891 and was posted to the 2nd Battalion, serving in Cyprus and then India, where he transferred to the Indian Staff Corps in January 1896 and served in the Tirah Campaign of 1897.
He joined the Indian Political Department in 1902 and served in the remote areas of Gilgit, Chilas, Chitral, and the Tochi, all in the Himalayas.
In the First World War, he served in the Indian Expeditionary Force in France and Flanders with Hodson's Horse, fighting at Mons.
Returning to the United Kingdom, he was appointed publicity secretary of the Public Schools Cadet Association in 1926 and secretary of the British National Cadet Association in 1931, holding both posts until his death.
He was appointed Companion of the Order of the Indian Empire (CIE) in the 1920 New Year Honours.