Gouraud was still in Morocco at the outbreak of war, having just been promoted brigadier general. He led the 10 Division in 1914 and the following year (15 May) was appointed to take over command of the French expeditionary force to the Dardanelles.
The French troops occupied the Asiatic side of the southern tip of the Gallipoli peninsula, alongside the British, and Gouraud led several attacks against the Turkish positions on Kereves Spur. Although the Dardanelles expedition was a British affair under command of Sir Ian Hamilton, the British general considered the French commander 'more as a coadjutor than as a subordinate' (Hamilton's diary, 14 June 1915, cited in C.F. Aspinall-Oglander, Military operations, Gallipoli , vol. 2, London, Heinemann 1932, p 71 ). After an attack on the Turkish strongpoint called the Quadrilateral on the Kereves Spur, Gouraud was severely wounded on 30 June, losing his right arm and suffering two broken legs. He was held in such high regard that King George V sent a telegram of regret to Sir Ian Hamilton. Despite his injuries, Gouraud was back in command of Fourth Army in Champagne by December.
When Lyautey became War Minister in December 1916, General Gouraud took over from him as Resident-General of Morocco and, after Lyautey's resignation and return, he returned to France, to his former army command. His Fourth Army faced the final German attack in July 1918. One of the units of his army had been fortunate enough to capture some German prisoners the day before the attack. They confirmed that the attack was to be launched, and Gouraud was able to apply the new elastic method of defence that the French commander-in-chief, General Pétain, had instituted. Thus the front line was only lightly held, and the German attack exhausted itself on the main defensive position, further back. The French were able to mount a counter-offensive around Villers-Cotteręts and the Germans were pushed back continuously from then on until the Armistice.
Gouraud's Fourth Army pursued the retreating Germans as far as Alsace, crossing the Meuse between Sedan and Mézières on 10 November 1918. He occupied northern Alsace until October 1919. Later he became the French High Commissioner in Syria and commander-in-chief of the Army of the Levant. He reached retirement age only in 1937.