Post shakedown training completed in time to participate in the Marianas campaign, McGowan arrived at Roi, Kwajalein Atoll, 31 May 1944.

The next day, during the invasion of Saipan she added fire support to her duties, disposing of a fuel dump and artillery emplacements endangering forces on the beach.

Next assigned to TG 53.1 she screened the transports carrying troops to Guam, remained through the initial landing operations, and then set course back to Saipan.

In the early hours of the 25th she participated in DesRon 54's torpedo attack on Japanese men-of-war, weakening them as they steamed Up Surigao Strait into defeat at the hands of Rear Admiral Jesse B. Oldendorf and his battleline.

As part of the antiaircraft screen off the San Fabian beachhead, she warded off the kamikaze suicide planes of the Japanese Special Attack Corps until the 14th, when she returned to escort work.

Throughout April and May they provided support for the troops fighting on Okinawa as they struck at enemy military and industrial targets from Formosa to Kyūshū.

Arriving in November she underwent overhaul, and on 30 April 1946 she decommissioned and entered the San Diego Group, Pacific Reserve Fleet.

Naval Force she cruised along the Korean east coast providing close fire support for U.N. troops and periodically took station off Wonsan to bombard.

Upon leaving the battle area she called at Buckner and Subic Bays, Singapore, Calcutta, Aden, Suez, and Gibraltar, arriving Newport 11 April 1953.

By late spring of 1958, as McGowan again returned to the eastern Mediterranean, Jordan and Lebanon were threatened with coups d'état in the continued struggle for leadership of the Arab world.

On 30 November 1960, at Barcelona, McGowan decommissioned and the following day became the Spanish Navy's Jorge Juan (originally with hull number 45, designated D 25 in 1961).