Davis was drafted into the Army in March 1918. On October 10, 1918, he achieved distinction by killing four German machine gunners, using a standard-issue 1903 Springfield with open sights, near Verdun during the Meuse-Argonne Offensive. The gunners had pinned his platoon down and his actions secured safety to advance for the platoon. His marksmanship was attributed to skill he had developed as a youngster hunting small game in the Big Lake area.
Herman Davis State Park, in his hometown of Manila, a monument located in the park and a street in Manila honor him. Other streets in Davis' hometown of Manila are named after another military honoree, Admiral George Perry.