Commissioned after the battle for the Atlantic had been decided, Lyman K. Swenson completed a Bermuda‑based shakedown cruise 25 June 1944 and prepared for duty in the Pacific.

Lyman K. Swenson left Ulithi on 21 October as part of DesRon 61, screening a replenishment group of ten oilers.

This group remained off the Philippines, refueling Admiral Halsey's aircraft carrier forces while the Imperial Japanese Navy suffered defeat at the Battle of Leyte Gulf, 24 to 26 October.

The new year dawned as she steamed with TG 38.1 on a 3,800‑mile raid which spewed destruction on Formosa, Luzon, and on Japanese shipping along the Vietnamese and Chinese coasts.

For the next four months aircraft and repair centers on Okinawa and the Japanese home island of Kyushu were the main targets for the strike group temporarily redesignated TG 58.1.

This campaign also provided an opportunity for shore bombardment as she shelled Okino Daita Shima early in March, and Minami Daito Jima in April and again in June.

With her sister ships, she then returned to San Pedro Bay, Leyte, to prepare for a mission which would continue until the surrender of Japan 71 days later.

Air opposition remained minimal; and, after DesRon 61's anti-shipping sweep into Sagami Wan, Honshū, on the night of 22/23 July, enemy ships also proved difficult to locate.

Lyman K. Swenson remained in enemy waters until after Japan's formal surrender on board battleship Missouri on 2 September.

On 20 September came the order to depart Tokyo Bay; and, after picking up additional passengers in Okinawa, Lyman K. Swenson proceeded back to the United States.

After performing patrol duties along the Chinese, Korean, and Japanese coasts, she steamed home to San Diego via Kwajalein, arriving 22 February.

Reacting with the characteristic speed of seaborn power, her group launched the first carrier based strike against North Korea 3 July.

In the aftermath of the Korean Armistice in July 1953, Lyman K. Swenson continued to average one six-month deployment annually in the western Pacific until 1960.

On 12 June 1964, Lyman K. Swenson departed Yokosuka for the United States, arriving San Diego 27 July via Australia.

With orders to proceed to the troubled coast of the Republic of Vietnam, Lyman K. Swenson departed San Diego 24 August 1965 and commenced fire support operations 4 October.

Arriving home on 6 October 1967, after another successful deployment, the veteran destroyer served as an engineering school ship and was assigned availability to the Development and Training Command into 1968.