Born in Tasmania, Whittle completed twelve months active service during the Second Boer War, before returning to Australia and enlisting in the Royal Navy where he served for five years as a stoker. Re-enlisting in the army, he was posted to the Army Service Corps, artillery, and Tasmanian Rifle Regiment prior to the outbreak of the First World War. Transferring to the Australian Imperial Force in 1915, Whittle joined the 12th Battalion in Egypt and embarked for the Western Front the following year.