Admiral Mayo was born in Burlington, Vermont, December 8, 1856 and graduated from the Naval Academy in 1876. During the Spanish-American War he served on the USS Bennington (PG-4) which was on duty on the Pacific Coast. In 1913, he was promoted to rear admiral and placed in command of the Fourth Division, Atlantic Fleet. While in command of the United States naval vessels at Tampico, Mexico, he demanded an apology from the Mexican commander and the firing of a salute of 21 guns to the United States flag to make amends for the unwarranted arrest of the officer and crew of a boat from the USS Dolphin (Despatch) while on duty at a wharf in Tampico on April 9, 1914. On June 16, 1915, he was designated as vice admiral, second in command of the Atlantic Fleet. He was appointed commander in chief of the Atlantic Fleet with the accompanying rank of admiral on June 19, 1916, and continued in command of all United States vessels in the Atlantic and European waters during the World War. He represented the United States at a naval conference of allied nations in London in September, 1917 and made an inspection trip to all United States naval activities in Great Britain, France, and Italy in 1918. He was awarded the Distinguished Service Medal with the citation: “Fore exceptionally meritorious service in a duty of great responsibility as commander in chief of the Atlantic Fleet in connection with the organization, training and maintaining of the fleet in a condition for war.” He was also awarded: “Grand Officer of the Legion of Honor, by the Government of France (exceptional services in the conduct of the war against the Central Powers), and Cordon of the Rising Sun, by the Government of Japan. Admiral Mayo reached the statutory retirement age of 64 years on December 8, 1920, but was continued on active duty as a senior member of the General Board until February 28, 1921, when he was released from further active duty at his own request. Upon Admiral Mayo’s retirement, Secretary Daniels wrote: “…In your well earned retirement, after a long and distinguished career in the Navy, you have gained the wealth of the confidence of your countrymen and the esteem of your associates and the lasting regard of those of use who have had the opportunity of properly appraising your great service in the years of the Navy’s greatest usefulness.”
Admiral Mayo was appointed Governor of the Naval Home, Philadelphia, from August 11, 1924, and served until August, 1928. He was commissioned Admiral on the Retired List of the Navy in accordance with the provisions of act of Congress June 21, 1930. He received the following medals: Spanish Campaign Medal, 1898; Mexican Service Medal 1914, USS Connecticut (Battleship No. 18); Victory Medal, Atlantic Fleet Clasp, commander in chief, Atlantic Fleet.