After exhaustive shakedown training had been completed, Howorth sailed 22 July 1944, screening a large convoy carrying marines toward Pearl Harbor. The ship arrived 7 days later and began a second training period in Hawaiian waters. Departing 25 August she joined the Seventh Fleet at Hollandia and, after brief stops at Purvis Bay and Manus on escort duty, she arrived at newly-taken Morotai 30 September. The next 2 weeks were spent in the busy Solomons on escort and antisubmarine duty.
Howorth steamed out of Humboldt Bay 16 October en route to Leyte. Arriving 22 October, three days after the initial landings, the ship guarded the transport anchorages while other fleet units decimated the Japanese in the epochal Battle for Leyte Gulf. She next made convoy voyages to Kossol Roads, Guam, and Manus before returning to Leyte for the Ormoc landings 7 December 1944. Next on the destroyer's schedule was the Mindoro operation. Howorth departed 12 December with Nashville and soon came under kamikaze attack. Upon arrival off Mindoro, the destroyer moved to Mangarin Bay for shore bombardment, aiding the assault troops by knocking out enemy emplacements. She was attacked by three suiciders, and while two were shot down close aboard, the third damaged Howorth's mast before splashing. Accordingly, the ship returned to Hollandia via Leyte, arriving 28 December. With the bases on Mindoro necessary for air support of Lingayen Gulf landings under construction, preparations continued for the invasion of Luzon.
The Lingayen operations got underway 9 January, and Howorth arrived with the first reinforcement group 13 January, after again fighting off suicide attacks en route. The ship was occupied until 1 February providing fire support to ground forces in the area, fighting off air attacks and patrolling to seaward of the Gulf. From Luzon she sailed to Saipan 15 February to take part in rehearsals for the next major amphibious assault, Iwo Jima.
Howorth arrived off Iwo Jima with the invasion fleet 19 February and, as troops landed for what was to be one of the hardest fought campaigns of the war, she began nearly a month of continuous air action and shore bombardment. With accurate ground support fire Howorth contributed much to the taking of this strategic island. Departing 14 March, she spent only a short rest at Ulithi before getting underway again, this time for the Okinawa invasion, last stop on the island road to Japan itself.
The veteran destroyer screened a transport group from Ulithi, arriving Okinawa with the huge invasion fleet 1 April. Once again she performed shore fire and screening duties, and shot down many attacking aircraft as the Japanese made a desperate attempt to stop the landings. While proceeding with cruiser St. Louis to station 6 April, Howorth and the larger ship were attacked by no less than eight kamikazes. While literally splashing planes on every quarter, the destroyer was crashed in the superstructure. Nine men were killed, but while the fires were being extinguished the last kamikaze was shot down astern.
Howorth was routed back to the United States for repairs, arriving Mare Island 2 May 1945. After shakedown training in early July, the ship sailed 15 July for Pearl Harbor and was en route to Adak, Alaska 15 August when the surrender of Japan was announced. She departed Adak 31 August for Japanese waters to screen flight operations and receive former prisoners of war before mooring at Yokohama 17 September 1945. Escort work carried Howorth to Pearl Harbor and back to Japan in October. She sailed finally from Tokyo Bay 11 November, arriving San Francisco 28 November. She decommissioned 30 April 1946 at San Diego and remained in the Pacific Reserve Fleet until March 1962 when she was sunk in torpedo tests off San Diego.
Howorth received five battle stars for World War II service.
Source: Dictionary of American Naval Fighting Ships, Naval History & Hereitage Command