At the outbreak of World War I, Moore became employed in France in war work, while Guggisberg rejoined the army. Moore founded the Women's Emergency Corps, which organised women volunteers, and established several leave clubs, acting as director general of the British Navy, Army and Air Force Leave Club in Paris. After the armistice, in Cologne, she organised a club for the army of occupation. In 1918 she was made a Commander of the Most Excellent Order of the British Empire for her services and was awarded the overseas medal and the Médaillon de reconnaissance. While her husband was a colonial governor, she served her country as Honorary Exhibition Commissioner for the Gold Coast at the British Empire Exhibition (1923–26), was Chairman of The Play Actors (1927–29), and Chairman of the Overseas Section of the Forum Club (1928–32). During World War II in Paris, she reestablished the British Leave Club in 1939. She fled the city on 11 June 1940, only a few hours before the entry of the Germans, attaching a notice to the doors of the club: "Temporarily Closed".