Boyden was ordered to the
Office of Naval Intelligence for a two-month preparatory indoctrination course and upon the completion, he embarked for
Havana,
Cuba and succeeded his former superior commanding officer,
Ross E. Rowell as
Naval attaché and Naval attaché for Air to the American Ambassador
George S. Messersmith. He had to face an attempts of enemy's spies, who raided his office in Havana and stole some documents in November 1940 and also abortive revolution in February 1941. Following the Japanese attack on Pearl Harbor and the United States entry into World War II, Boyden assisted in the evacuation of total 450 civilians dependents of the Naval personnel at
Guantánamo Bay and was praised by the Commandant of the Naval Base there, Rear admiral
George L. Weyler. Boyden was promoted to the temporary rank of lieutenant colonel on January 26, 1942, and assumed additional duty as Naval attaché for
Haiti two months later. He was later promoted to the temporary rank of Colonel on October 13, 1942, and served in
Cuba until August 1943, when he was succeeded by Colonel
John N. Hart and ordered back to the United States for new assignment. For his service in Cuba, Boyden was decorated with
Order of Naval Merit, 1st Class and Red Cross Medal of the Order of Honor and Merit, rank Commander by the Cuban Government. Boyden then reported at the
Headquarters Marine Corps in
Washington, D.C. and was attached to the
Division of Aviation under Major general
Louis E. Woods. However he remained there only for two weeks and was transferred to
Marine Corps Air Station Cherry Point,
North Carolina, where he assumed duty as Assistant Wing Commander,
3rd Marine Aircraft Wing under Brigadier general
Claude A. Larkin. He participated in the training of replacements Marine air crews until December 1943, when he was ordered to the
Army Air Forces School of Applied Tactics at
Orlando Army Air Base,
Florida, and completed one-month instruction there. He was subsequently ordered to the
Army Command and General Staff College at
Fort Leavenworth,
Kansas, and completed another one-month course of instruction there. Boyden was then sent to the Army and Navy Staff College in
Washington, D.C. and completed his third instruction after two months in April 1944. He was then assigned to the headquarters,
Marine Air, West Coast in
San Diego,
California, under Major General
Francis P. Mulcahy. In July 1944, Boyden was then ordered to
Espiritu Santo and assumed duty as Chief of Staff,
2nd Marine Aircraft Wing (2nd MAW) under Major general
James T. Moore. The 2nd MAW just returned from combats in Northern Solomons and served mainly to train and outfits Marine air units through the summer of 1944. Following the
Battle of Peleliu in November 1944, the 2nd MAW moved there and served as Garrison Air Force, Western Carolines. Boyden was largely responsible for preparing the wing for the operation, procuring equipment and personnel, arranging transportation, assigning and training officers and non-commissioned officers to specific duties, and coordinating the entire organization into a smooth functioning combat unit. By the end of April 1945, the 2nd MAW was ordered to
Okinawa to support the landing troops. Boyden was in command of the rear echelon after embarkation of the assault unit, and was responsible for completing preparations for the movement of his troops and equipment. Landing on Okinawa on May 1, he was indefatigable in carrying on the details of administration under the new Commanding General of the Wing,
Francis P. Mulcahy, being especially diligent in arranging for the security of the camp and effecting physical improvements. He carried on his work in exposed areas heedless of danger, and his disregard of personal safety was an inspiration to the entire command. For his service during the Okinawa campaign, Boyden was decorated with
Legion of Merit with
Combat "V" and also received
Navy Presidential Unit Citation. ==Postwar service==