Francis Duffy was born on May 2, 1871, in Cobourg, Ontario, Canada, and later immigrated to the United States. He was ordained as a priest in the Archdiocese of New York on September 6, 1896, and served with the 69th Infantry Regiment of the New York National Guard during the Spanish-American War in 1898. He earned his doctorate at The Catholic University of America in 1905, and joined the New York National Guard as a chaplain in 1914, serving as chaplain of the 69th Infantry Regiment from 1914 until his death on June 26, 1932. While serving with the Fighting 69th (renamed the 165th Infantry Regiment during World War I), LtCol Duffy served along the Mexican Border during the Punitive Expedition in 1916; during World War I in the campaigns at Rouge Bouquet, Champagne, Chateau-Thierry, St. Mihiel, and Meuse-Argonne; and on occupation duty in Germany until early 1919. Francis Duffy was buried at the Saint Raymonds Cemetery in the Bronx.

His Distinguished Service Cross Citation reads:

The President of the United States of America, authorized by Act of Congress, July 9, 1918, takes pleasure in presenting the Distinguished Service Cross to First Lieutenant (Chaplain) Francis Patrick Duffy, United States Army, for extraordinary heroism in action while serving as Chaplain with the 165th Infantry Regiment, 42d Division, A.E.F., in the village of Villers-sur-Fere, France, from 28 to 31 July 1918. Chaplain Duffy devoted himself tirelessly and unceasingly to the care of the wounded and dying. Despite a constant and severe bombardment with shells and aerial bombs, he continued to circulate in and about two aid stations and the hospitals, creating an atmosphere of cheerfulness and confidence by his courageous and inspiring example.