Born in Wellington, Shout had served in the Second Boer War as a teenager. He rose to sergeant and was mentioned in despatches for saving a wounded man before being discharged in 1902. He remained in South Africa for the next five years, serving as an artilleryman in the Cape Colonial Forces from 1903. With his Australian-born wife and their daughter, Shout immigrated to Sydney in 1907. The family settled in Darlington, where Shout worked for Resch's Brewery as a carpenter and joiner. He was also active in the part-time Citizens' Forces, being commissioned just prior to the outbreak of the First World War. In August 1914, he joined in the Australian Imperial Force (AIF) for active service overseas and was appointed a lieutenant in the 1st Battalion. After training in Egypt, he took part in the Anzac landings at Gallipoli on 25 April 1915. For his leadership during the invasion and its immediate aftermath, Shout was awarded the Military Cross and later mentioned in despatches. Shout's three gallantry awards at Gallipoli made him the most highly decorated member of the AIF for the campaign.