Following conversion work at Newport Beach, California, and shakedown out of San Pedro and San Diego, California, "Gallup" departed San Diego on 1 June 1944 for the Pacific war zone. Conducting anti-submarine patrol en route, she arrived at Nouméa, New Caledonia, on 21 June 1944, and began escort and patrol duties in the waters of New Caledonia, New Guinea, and Australia with Escort Division 43. On 17 August 1944, she bombarded enemy strongholds to support landings on Biak Island at Blue Beach, north of the Wardo River by units of the United States Armys 41st Infantry Division; she continued to fire until the troops had completed their landing and secured the beach. Again, on 25 August 1944, "Gallup" lent support to the conquest of Biak by shelling the beaches between Menoerar and Cape Warari. After Biak had been secured, she returned to her duties with Escort Division 43 until 12 October 1944.