During the early fall of 1919, Southard completed fitting-out and sailed for the Florida coast for shakedown. She next headed for New York to join six other destroyers in escorting HMS Renown out to sea as that warship departed carrying Edward, the Prince of Wales, after his visit to the United States. On 19 November 1919, Southard departed Newport, R.I., for duty with the naval forces in the eastern Mediterranean. For about a year, she operated in the Adriatic Sea. She then departed the Dalmatian coast; transited the Suez Canal; and, after calling at ports in Egypt, Arabia, India, and China, put in at Cavite in the Philippines on 16 February 1921. Southard underwent repairs at the navy yard there until 21 March, when she resumed operations. On 27 August 1922, she sailed for the United States and arrived in San Francisco, California, on 2 October. From there, she moved on to San Diego, where she was decommissioned on 7 February 1922.
After almost seven years in reserve, Southard again flew a commissioning pennant on 6 January 1930. She operated off the west coast of the United States throughout 1930 and in the vicinity of the Panama Canal during the first months of 1931. For the next nine years, Southard continued operations in the Pacific with the Battle Force. The only exceptions to this schedule came in 1934 and 1939 when she made short cruises in the Atlantic. In 1940, she was converted to a high-speed destroyer minesweeper and, on 19 October, was reclassified DMS-10.
Though stationed at Pearl Harbor when war broke out in the Pacific, Southard was at sea during the Japanese attack on 7 December. Two days earlier, she had departed that base to participate in exercises in the vicinity of Johnston Island. The destroyer minesweeper returned to Oahu two days after the attack and patrolled the approaches to Pearl Harbor until 23 January 1942. After escorting a convoy to San Francisco and back, on 15 February Southard resumed patrols in Hawaiian waters. On 20 May, she again exited Pearl Harbor in the screen of an eastbound convoy. The ships reached San Francisco on the 31st, and Southard spent the next 10 days in restricted availability in the Mare Island Navy Yard. She reentered Pearl Harbor on 1 July and, nine days later, stood out for the South Pacific.
Stopping along the way at both British and American Samoa, she arrived at Tongatabu, Fiji Islands, on 22 July. She departed three days later, stopped at Éfaté Island in the New Hebrides, and made Guadalcanal by 7 August. Southard participated in the opening bombardment of Florida Island; then joined the minesweeping force in a sweep to the south of Gavutu Island and through Lengo Channel. On the 8th, about 20 high-altitude bombers attacked the transport area, and Southard succeeded in splashing at least one enemy plane.
When the beachhead on Guadalcanal had been successfully established, Southard settled down to the risky routine of screening the convoys from New Caledonia and the New Hebrides to the Solomons. For almost eight months, she steamed back and forth between Espiritu Santo, Éfaté, Nouméa, Tulagi, Purvis Bay, and Guadalcanal. There were frequent air attacks, and submarines prowled the sea-lanes.
Early in the morning of 10 November, while passing between San Cristobal and Guadalcanal en route to Aola Bay, Southard encountered an enemy submarine steaming on the surface. She immediately slowed to 10 knots and opened fire. The submarine submerged, and Southard commenced her first depth-charge attack. The destroyer minesweeper lost contact with her adversary and did not regain it again until 0607, almost three and one-half hours later. Over the next three hours, Southard made five more depth-charge runs. After the last barrage, oil was sighted on the surface; and she moved in to investigate. Upon reaching the slick, Southard’s crew could find no further evidence of damage, and she steamed on through the slick. When she reached a point about 2,000 yards on the other side of the slick, the submarine surfaced almost vertically-exposing her whole conning tower, her hull forward of the tower, and part of her keel. Then the bow dropped about 10 degrees, and the submarine sank rapidly by the stern. Though absolute confirmation of a kill was never received, all evidence strongly indicated that Southard was the victor.
Following a liberty and recreation excursion to Brisbane, Australia, and six days in dry-dock at Sydney, Southard returned to patrol and convoy duty in early January 1943. On 20 March, she stood out of Nouméa in company with Hovey (DMS 11), Stringham (APD 6), and Sonoma (AT 12) towing Aulick (DD 596). This task unit stopped at Suva Harbor, Fiji, on the 25th and departed the next day to continue on to Pago Pago, Pearl Harbor, and ultimately to San Francisco. Southard entered the Mare Island Navy Yard on 19 April and remained until 8 June. By the 15th, she was in Pearl Harbor again and, nine days later, headed back toward the South Pacific. She reached Dumbea Bay, New Caledonia, on 6 July 1943.
Her return to the western Pacific meant a resumption of patrol and convoy escort duty to support the continuing Solomons campaign which, by this time, had progressed farther north. On 30 October, she joined a convoy off Tetere Point, Guadalcanal, and steamed for Bougainville. The convoy arrived off Cape Torokina the next day, and Southard joined other elements of the fleet in bombarding Bougainville. After minesweeping operations in Empress Augusta Bay, she made for Florida Island, entering Purvis Bay on 3 November. Four days later, she returned to Bougainville to investigate the shoals along the approaches to Empress Augusta Bay; then, she resumed patrols off Guadalcanal.
These patrols and cruises with convoys occupied Southard’s time until 21 November, when she passed through Lengo Channel bound for Nouméa. From 25 November to 16 December, Southard stayed in the vicinity of New Caledonia, participating in drills and screening ships into and out of Nouméa. On 17 December, she entered Suva Harbor with a convoy and, two days later, got underway for Guadalcanal.
Upon her reentry into the Solomons, she took up the familiar routine of patrols and screening supply ships. The apparent monotony was broken on 22 January. While escorting Cache (AO-67) from Florida Island to Espiritu Santo, Southard had an opportunity to sharpen her antisubmarine warfare skills when a Japanese submarine torpedoed her charge. Her hunting, however, was cut short by the more important task of covering the limping oiler’s retirement to Espiritu Santo.
In late February, Southard visited Auckland, New Zealand. She returned to the Solomons in March, patrolled the Guadalcanal area, and conducted exercises in the Russell Islands. Her field of operations was expanded in April and May to include parts of the Bismarck Archipelago as she began escorting convoys to Borgen Bay, New Britain. By 10 May, she was back in Espiritu Santo; and, a week later, she set sail for the United States and overhaul. She took on fuel at Funafuti on 19 May, provisioned and fueled at Pearl Harbor on the 24th and 25th and entered San Francisco Bay on 31 May. Southard commenced overhaul at the Mare Island Navy Yard the next day.
Two months later, the revitalized destroyer minesweeper headed back to the war. She made Pearl Harbor on 5 August and, on the 12th, sortied with six escort carriers and five other destroyer-type ships, bound for the Solomons. Twelve days later, the task group entered Purvis Bay. Southard stood out again the following day for exercises in the Russells.
On 4 September, she rendezvoused with a task force off Guadalcanal, arrived in the Palaus on the 12th and swept mines off the coasts of Peleliu and Anguar. On the 24th, she fueled and replenished at Manus in the Admiralty Islands, then returned to the Palaus for patrols and screening duties. She reentered Seeadler Harbor on 4 October to prepare for the invasion of the Philippines at Leyte.
Southard sortied from Manus with the Dinagat Attack Force on 10 October and began sweeping Leyte Gulf on the 18th. She swept mines in the gulf again on the 19th and made an exploratory sweep of Surigao Strait on the 20th. On the 24th, the destroyer minesweeper joined the screen of Carrier Group 77.4 and remained so employed until the 26th. Back in Seeadler Harbor by 30 October, Southard spent all of November and most of December engaged in drills and availability at Manus.
Two days before Christmas 1944, she rendezvoused with TG 77.6 and headed for Leyte Gulf. From there, the task group moved on to Luzon and the Lingayen assault. Southard began minesweeping operations at Lingayen on 6 January 1945. Late that afternoon, while she was fighting off a kamikaze attack, one of the suicide planes crashed Southard abaft her stacks. The plane’s engine embedded itself in the ship while its fuselage ricocheted off her starboard side, tearing a trough six feet wide in her deck as it went. Southard quickly cut loose her sweep gear and retired to make emergency repairs.
Within 14 hours, she was back in action sweeping mines. The plucky ship continued operations for five more days before departing the Lingayen area. She returned to San Pedro Bay on 14 January for further repairs; then, on 4 February, headed east toward Hawaii. She stopped at Ulithi on the 6th and at Guam two days later. Southard departed from the Marianas on the 13th and arrived in Pearl Harbor on George Washington’s birthday. She underwent extensive repairs at Pearl Harbor and did not leave Hawaiian waters until 4 May. She stopped at Eniwetok on the 12th; then, in company with Clinton (APA-144) and Buckingham (APA-141), continued on to the Marianas. On 21 May, she sailed from Guam to Saipan and, two days later, got underway for Okinawa.
On the day of her arrival at Nakagasuku Wan, Okinawa, Southard almost suffered another suicide crash as an attacking kamikaze splashed a scant 15 yards ahead of the destroyer minesweeper. For the next three months, she swept mines, screened transports, and delivered mail to the fire support units around Okinawa. On 15 August 1945, hostilities between the United States and the Japanese Empire ceased. Southard remained in the Ryukyus for the rest of August, undergoing inspection and survey. By 15 September, the survey team determined that she should be moved to the rear area for further inspection and repair. However, two days afterward, while maneuvering at anchor during a typhoon, her screws were fouled by a drifting antisubmarine net; and she was grounded on a pinnacle reef off Tsuken Shima. She was floated clear of the reef, and her propellers were cleared by divers on the 18th. Later, while still waiting to move to the rear area, on 9 October, Southard was wrecked on another reef about 1,000 yards southwest of Tsuken Shima. The next day, the officers and crew, save the commanding officer and a skeleton crew, were removed. The destroyer minesweeper was declared a total loss; and, on 5 December 1945, she was decommissioned. Southard was struck from the Navy list on 8 January 1946, and her hulk was destroyed six days later.
Southard received 10 battle stars for World War II service.