Screening 7th Fleet flagship during the invasion of Leyte Gulf, "Mullany" fired to help drive off nine separate enemy air attacks from 20 to 29 October, then sailed for overhaul at San Francisco. After training near Hawaii in January 1945, she joined Task Force 54 (TF 54) for the invasion of Iwo Jima, to which she escorted troop transports. After firing in the preinvasion bombardment, she supported troops landing and fighting ashore, hitting caves and machinegun nests on Mount Suribachi 19 February.