In April 1917, Rear Admiral Fullam became Commander-in-Chief Patrol Force, U.S. Pacific Fleet, and was senior officer in command of the Pacific Fleet during the absence of the Fleet's Commander-in-Chief in South Atlantic waters. The merit of his service in such responsible positions was recognized with the award of the Navy Cross. In early 1918 Vice Admiral Kantarō Suzuki (who later became the 42nd Prime Minister of Japan from April 7, 1945 to August 17, 1945) brought his two cruisers and to San Francisco and "banqueted" with Rear Admiral Fullam after receiving harbor entrance by Rear Admiral Fullam. Continuing his duties as Commander-in-Chief, U.S. Pacific Fleet, throughout the World War until 1 August 1919, he coordinated with the Japanese and British forces all ship movements while patrolling the whole Pacific from Alaska to the Panama Canal Zone. This was in order to check all German activities.