After initial shakedown exercises off the East Coast of the United States, Mack assembled with ComCortDiv 82 at Norfolk, Virginia, 17 to 20 October 1944, and departed on 21 November for the Panama Canal en route to the Pacific Ocean.

Two days after the signing of the surrender terms, Mack began air-sea rescue patrols between the Philippines and the Palaus, returning to escort duty on 16 August to accompany a slow tow through the “typhoon belt" to Okinawa.

While standing by for escort duty at San Fernando, 10 January 1946, Mack answering a distress call from FS-74, proceeded through heavy weather to the disabled ship's position.

Departing Subic Bay 11 February, Mack joined Escort Division 33 and set course for Qingdao, China, where the U.S. 7th Fleet was lending support to the U.S.-China policy; standing by to protect, if necessary, American interests during the fighting between the Nationalist forces and the Communists.

Arriving on 20 February, Mack took part in training exercises off the China coast and made brief trips to Shanghai and Taku before departing Chinese waters on 15 April, for Okinawa to take on naval passengers en route to the United States.