Edgcomb enlisted May 8, 1861 in the 23rd New York Infantry at Cortland, New York to serve two years. At Second Manassas he tried to rescue a wounded comrade from the Stone House during the Union retreat, August 30, 1862. Private Edgcomb was mustered out of the army on May 22, 1863 at Elmira, New York.

Source: "Annual Report of the Adjutant-General of the State of New York. For the Year 1899."