Hamilton received command of the 3rd Division in June 1914, and at the outbreak of the First World War immediately took the force to France with the British Expeditionary Force in the II Corps under General Horace Smith-Dorrien. During August and September, Hamilton's force was almost continuously engaged, fighting at the battle of Mons, Le Cateau and along the lines of the Marne River. In exhausting combat, casualties were massive and Hamilton came close to death on 26 September when a shell landed just feet away from where he and two other generals were discussing operations. Luckily for them however, the munition did not detonate. In spite of difficult conditions of the campaign, Hamilton shared his men's hardships and was frequently in the front line, earning the affectionate nickname "Hammy" from his subordinates.