After the Attack on Pearl Harbor on 7 December 1941, her convoy duties were extended to include three runs to Scotland and single trips to Nova Scotia and Greenland.

In October 1942, after amphibious training in Chesapeake Bay, Swanson joined the invasion fleet sailing for French North Africa.

On 10 July, the night before the landings, she collided with Roe while investigating radar contacts and went dead in the water with a flooded fire room.

With repairs complete, Swanson resumed escort duties in the Atlantic until sailing on 7 January 1944 to join the 7th Fleet off New Guinea.

She screened the carriers Franklin, Enterprise, and San Jacinto, while they launched airstrikes on Bonins, Ulithi, Yap, Palau, Okinawa, Taiwan, and while they provided air support for the Philippine landings on 20 October.

For the rest of 1944 and early 1945, she was engaged in air-sea rescue, antisubmarine, and radar picket patrols between Iwo Jima and Saipan and served as the headquarters for the commander of the group.

USS Swanson was awarded the Navy Occupation Service Medal for the period of 8 Sept to 23 Oct 1945 This article incorporates text from the public domain Dictionary of American Naval Fighting Ships.