Enlisting in the Royal Naval Volunteer Reserve on 22 August 1914 and commissioned in September, he served in a wide variety of theatres and actions in the First World War, including the Grand Fleet at Scapa Flow, Harwich light cruisers, Admiral Troubridge's mission to the Danube, naval siege guns at Flanders, the Zeebrugge Raid in which, commanding a rear gun on , he was severely wounded, necessitating the amputation of his right arm, and, finally, in the Russian campaign, commanding an armoured train on the line south of Archangel. These experiences were all recounted in his colourful 1920 war memoir, "By Sea and Land". His war service also brought the awards of the Distinguished Service Order, Distinguished Service Cross and Bar, French Croix de guerre, and the Serbian Silver Medal.