"Isherwood" sailed for Pearl Harbor 26 August 1944 to take part in the long-awaited invasion of the Philippines, scheduled for October. She arrived at Manus on 4 October and steamed into Leyte Gulf with the assault force 20 October, carrying out escort and patrol duties during the first days of the operation. She also provided gunfire support and night illumination fire. "Isherwood" remained in the assault area during the giant four-part Battle for Leyte Gulf 23–26 October, in which the Japanese surface fleet was all but annihilated. During November the ship escorted convoys from advance bases to the Philippines in support of the buildup there.