Gale was posted, in the summer of 1916, to the 164th Machine Gun Company, which was in support of the 164th (North Lancashire) Brigade of the 55th (West Lancashire) Division. With his company, he fought in the Battle of the Somme and, towards the end of the year, served in the Ypres Salient. He was promoted to the temporary rank of lieutenant on 1 November 1916, and to the substantive rank on 1 July 1917. He was next involved in the Capture of Wytschaete in June 1917 but was not involved in the Passchendaele offensive, as he was suffering from both mental and physical exhaustion, and was sent to England on leave, and diagnosed with pyorrhoea. He returned to service in January 1918, although now serving with the 126th Machine Gun Company of the 126th (East Lancashire) Brigade, part of the 42nd (East Lancashire) Division. Among the fellow officers in his new company was Major Edwin Flavell, who was to serve in Gales' later career. On 23 February the company merged into the 42nd Battalion, MGC. It was during his service as a subaltern in France that he won the Military Cross (MC). During the German spring offensive launched by the German Army in mid-March 1918, Gale was awarded his MC for 'conspicuous gallantry and devotion to duty'. He covered the retreat of a British infantry unit with his machine gun section, and when an artillery shell landed by a gun limber, he unhitched the killed and wounded horses under heavy fire to allow the limber to be moved away. Soon promoted to captain, Gale continued to serve on the Western Front, taking part in the Hundred Days Offensive, until the end of the war on 11 November 1918.