Laid down alongside Benson at Bethlehem Steel’s Fore River Shipyard, Quincy, Massachusetts on 16 May 1938, Mayo’s construction progressed slowly. When launched on 26 March 1940, nearly 22 months later, she was named for the late Commander-in-Chief of the US Atlantic Fleet during World War I.
The “Mighty Mayo” served the US Navy actively from 18 September 1940 through 18 March 1946. Prior to engagements with German tanks and aircraft during the invasion of Italy, Mayo supported convoy runs to and from Europe on an almost-continuous basis from the early months of 1941 through 1945. Firing on German U-boats and supporting the landing of Marines on Iceland in pre-Pearl Harbor 1941 were stressful and risky duties.
In December 1940, Squadron 7 was reformed at Newport, Rhode Island and until the end of the European War was actively engaged in escort duties throughout the Atlantic and Mediterranean Theaters.
After shakedown, Mayo joined the expanding neutrality patrol and escorted Marines to Iceland in July 1941 to take protective custody of this key island. As President Roosevelt and Prime Minister Churchill agreed to the Atlantic Charter during the second week in August, Mayo guarded their meeting by patrolling off Argentia, Newfoundland.
The formal entrance of the United States into World War II lengthened her convoy assignment beyond the western Atlantic. In the summer 1942, escort of slow merchant convoys out of Boston gave way to duty with fast troop transports out of New York. U‑boats and bad weather were not the only dangers to be encountered. When the transport Wakefield caught fire on 3 September, Mayo swiftly moved alongside the burning ship and removed 247 survivors.
For the invasion of North Africa, Mayo appeared at Casablanca, Morocco, 12 November, four days after D‑Day, to protect the landing of reinforcements. A retraining period at the end of the year in Casco Bay, Maine, temporarily interrupted convoy assignments.
In August 1943, Mayo and DesRon 7 joined the Eighth Fleet in the Mediterranean. She gave fire and antiaircraft protection to the beachhead at Salerno, Italy on 8 September and again at Anzio beginning on 22 January 1944.
At 2001 on the 24th, a sudden explosion killed seven and wounded 25 of her crew while almost breaking her in two. Despite a gaping hole at the waterline, starboard, she survived a tow back to Naples for a temporary patch, and 3 March began the long tow back to the States. At the New York Navy Yard beginning on 5 April, Mayo required four months for repairs. Thereafter, she made a voyage to Trinidad and four to Europe before Germany was conquered.
On 5 May 1945, DesRon 7 sortied from New York for the western Pacific, and at Pearl Harbor joined fast carrier TG 12.4. Planes from this group struck Wake Island as a training gesture 20 June as the ships sailed on westward. Upon reaching Ulithi, Mayo began a series of escort missions to Okinawa. The “Tank Buster” of Salerno was now nicknamed the “Mayo Maru” and almost immediately began escorting transports and materials to Okinawa for a possible invasion of Japan.
On 24 August she got underway escorting occupation troops which were landed on Honshu 2 September. Arriving at Tokyo Bay early on 2 Sept 1945, Mayo passed and anchored in view of USS Missouri for the surrender ceremony. Thereafter, she shepherded additional troops from the Philippines and Okinawa before sailing from Yokohama 5 November for San Diego and Charleston, arriving 7 December. She decommissioned 18 March 1946 and went into reserve at Orange, Tex., where she remains into 1969.