In World War II, then Brigadier General Moore fought in the Bataan Campaign, later becoming the commander of the Harbor Defenses of Manila and Subic Bays in the Philippines, both during the 1941–42 Japanese invasion. He was given command of the Philippine Coast Artillery with roughly 5,000 men and four forts to defend Corregidor. On May 6, 1942, General Jonathan Wainwright surrendered the Corregidor garrison at about 1:30 p.m., leading himself and General Moore to be captured by the Japanese, and held as a POW, later liberated in August 1945. General Moore was awarded the Distinguished Service Cross and Distinguished Service Medal while in captivity.