Following graduation in 1919, Johnson served in the battleship USS Delaware (BB-28) during Haitian Campaign. He joined the USS Penguin (AM-33) in 1923 when she was ordered on Yangtze Patrol. In 1928 Johnson was ordered to Asiatic Station and while en route to China served as navigator of schooner yacht Atlantic in the Spanish ocean race, New York to Santander. In 1929 he served as aide and flag lieutenant to CinC U.S. Asiatic Fleet. Following duty with the CNO, Johnson reported in 1936 as a member of the Naval Mission to Brazil. During World War II he was CO of the USS President Adams(AP-38/APA-19) in the South Pacific, landing troops at Cape Torokina, Bougainville, and the Solomon Islands. In 1945 Johnson was CO of the USS Springfield (CL-66), providing escort protection for President Franklin Roosevelt to Yalta, then joining the Fifth Fleet in Pacific campaign. He was Director of Naval Intelligence until his retirement in 1952.