Upon the outbreak of World War I, Edwards was placed in charge of the Department of the Northeast, comprising all the New England states. In August 1917, four months after the American entry into the war, he was promoted to the rank of major general in the National Army and given the task of organizing the 26th Division. The division, an Army National Guard formation, arrived on the Western Front in September 1917, the first complete American division to do so. The division also became the first complete American division to go into combat at Chemin-des-Dames, France, in February 1918, where they remained for 46 days.