Margaret is named in a 1922 history of the Pittsburgh Red Cross as a St. Francis nurse graduate who was "in active service with the American Expeditionary Forces and in the United States."

Margaret T. Gallagher Service Info.: NURSE US ARMY WORLD WAR I; Birth Date: 27 May 1884; Death Date: 28 Apr 1958; Service Start Date: 1 Apr 1918; Interment Date: 2 May 1958; Cemetery: Bay Pines National Cemetery Cemetery; Address: P.O. Box 477 Bay Pines, FL 33744; Buried At: Section 29 Row 2 Site 11. [She was honorably discharged on July 12, 1919.]