On 30 April 1943, while screening in convoy, the ship ran aground off the southern coast of Guadalcanal and, after jettisoning heavy gear and ammunition, she was eased off the reef by three tugs.

Repairs completed, she participated in the New Georgia Group operations (30 June – 13 July) and while under heavy attack she effectively bombarded the enemy shore batteries during the invasion of Rendova.

On 22 January, while going to the rescue of the torpedoed oiler Cache, Buchanan hunted down and sank the Japanese submarine RO-37 in 11°47′S 164°17′E / 11.783°S 164.283°E / -11.783; 164.283.

She participated in the Battle of Karavia Upon completion of overhaul and refresher training Buchanan returned to the Pacific and served with the transport screen during the assault and capture of the southern Palaus (6 September – 14 October 1944).

During the remainder of World War II she participated in the Iwo Jima invasion (15 February – 5 March), Okinawa operation and supporting 3rd and 5th Fleet raids (16 March – 30 June); as well as the 3rd Fleet operations against Japan (10 July – 15 August 1945).

The following day she carried General MacArthur to the battleship Missouri where he accepted the Japanese surrender and then returned him to Yokohama.

Buchanan was recommissioned 11 December 1948 at Charleston and underwent shakedown and refresher training with a nucleus Turkish crew aboard.