Her stay in Hawaii lasted until 23 October when she steamed out of Pearl Harbor in company with the battleship , bound for duty in the western Pacific with the Fast Carrier Task Force. Steaming via Eniwetok, the destroyer entered Ulithi lagoon on 5 November. "Allen M. Sumner" remained at Ulithi until 19 November at which time she departed the atoll to join Task Group (TG) 38.4 at sea. After rendezvousing with the carriers, she accompanied them to waters near Yap Island whence the aircraft carriers launched air strikes on 22 November before reentering Ulithi that same day. The destroyer remained there for 5 days and then returned to sea, bound for newly invaded Leyte in the Philippines. She arrived in San Pedro Bay on 29 November and began patrolling Leyte Gulf. That duty—punctuated intermittently by air alerts—lasted until the evening of 2 December when "Allen M. Sumner" set course for Ormoc Bay in company with the destroyers and .