Savannah then supported Operation Avalanche, the Allied invasion of mainland Italy at Salerno. On 11 September 1943, while bombarding German shore defenses in Salerno Bay, Savannah was among cruisers which came under heavy German aerial attack. The cruisers and Britishfighters drove off nearly 60 German bombers before a Dornier Do 217K-2 bomber hit Savannah with a Fritz Xradio-controlled, armor-piercing guided bomb. It pierced the armored roof of the No. 3 gun turret immediately in front of the ship's bridge, passed through three decks into the lower shell-handling room, and exploded there, blowing a gaping hole in the ship's bottom, and tearing open a seam in the ship's port side. For 30 minutes, secondary explosions in the gun room hampered fire-fighting efforts.
Kirwin was at his battle station as turret officer in No. 3 turret when the bomb struck. He remained behind in the turret to supervise the evacuation of as many men as possible, was overcome by heat and toxic smoke, and died at his station. Kirwin was posthumously awarded the Navy Cross.
In the autumn of 1964, the high-speed transport USS Earle B. Hall (APD-107) suffered a major engineering casualty that caused her to lose all power, and she was deemed not worth repairing. Kirwin was chosen to replace her. Accordingly, on 30 November 1964, Kirwin arrived under tow at Naval Amphibious Base Little Creek at Virginia Beach, Virginia, and was berthed alongside Earle B. Hall. There Kirwin underwent reactivation, with Earle B. Hall's crew readying her for recommissioning. On 15 January 1965, after almost 19 years in reserve, Kirwin was recommissioned and Earle B. Hall was simultaneously decommissioned, with Earle B. Hall's crew transferring to Kirwin.
On 29 November 1965, Kirwin departed for the Caribbean to join Task Force 184 for amphibious warfare and antisubmarine exercises. She returned to Little Creek on 16 December 1965.