With the invasion of the Philippines scheduled for mid-October 1944, "Callaghan" steamed in the screen of the carrier force conducting essential preliminary neutralization of Japanese airfields in Formosa and Okinawa. During a heavy enemy air attack on 14 October, "Callaghan" joined in downing several planes. Sailing on to stand guard off the invasion area on Leyte, "Callaghan"s force contributed air power in the decisive Battle for Leyte Gulf, helping to ensure that the Allied advance in the Philippines against the Japanese efforts to break up the landings. After pursuing the Japanese moving north, "Callaghan" returned to support the Philippine operations, with the 3rd Fleet, for air strikes on Luzon. En route on 3 November, was torpedoed, and "Callaghan" stood by to protect the stricken light cruiser until relief forces arrived, when "Callaghan" was able to rejoin her group for the strikes. Through December, she participated in more air strikes on the Central Philippines, and in January 1945, the destroyer sailed with the 3rd Fleet for air raids on Formosa, Luzon, Indo-China, Hong Kong, and the Nansei Shoto.