John Haddoo answered the call to service from the town of Hooksett, New Hampshire. By the mid-1870s, he had found his way into the ranks of the United States Army, serving as a Corporal with Company B of the 5th U.S. Infantry. His service placed him at the heart of the Great Sioux War, a period of intense conflict across the Western territories.

Between October 1876 and January 1877, Haddoo’s unit was engaged in grueling winter campaigns across the Montana Territory. This period was defined by harsh conditions and constant skirmishes following the Battle of the Little Bighorn. Haddoo specifically distinguished himself during the operations at Cedar Creek and other engagements throughout that winter.

The culmination of this campaign took place in the rugged terrain of the Wolf Mountains. Throughout the months of sustained combat, Haddoo’s conduct remained exemplary. For his repeated bravery and consistent courage under fire during these winter months, he was officially cited for gallantry in action.