Panamint was laid down as SS Northern Light (MC hull 1354) on 1 September 1943 by the North Carolina Shipbuilding Company, Wilmington, N.C.; launched 9 November 1943; acquired by the Navy 29 February 1944; converted to a general communications vessel at the Todd-Hoboken Yard, Hoboken, New Jersey, N.J.; commissioned 14 October 1944.

On 1 March Panamint sailed for Cape Esperance, Guadalcanal in company with Transport Group ABLE to stage for the forthcoming invasion of Okinawa.

Panamint, part of the Northern Attack Force, served as flagship of Rear Admiral Lawrence F. Reifsnider, Commander Amphibious Group 4.

During the capture of Ie Shima and until mid-June 1945 Amphibious Group 4 retained responsibility for naval support of troop operations in northern Okinawa.

Panamint put her rudder hard right at full speed and swung on the anchor to a position paralleling the course of the approaching plane and torpedo.

The plane erupted into flames, passed 150 yards astern of Panamint, glanced off the cargo boom of Dutch ship Tjisadane, and splashed into the sea.

On 12 August 1945 the ship sailed for Adak, Aleutian Islands, where she reported for duty to Commander North Pacific Force and Area.

On 29 August Vice Admiral Frank Jack Fletcher, Commander North Pacific Force and Area, hoisted his flag on Panamint.

On 7 September the flagship pulled away from the anchored task force and proceeded to a rendezvous point to await the Japanese surrender ship from nearby Ōminato Naval Base.

On the morning of the 8th the massive naval force got underway led by a Japanese frigate through the mineswept channel and Tsugaru Strait leading to Ōminato Anchorage.

Panamint next served as flagship for Rear Admiral Arthur Dewey Struble, Commander Minecraft Pacific Fleet.

On 1 July 1946 she covered Joint Army-Navy Task Force I's "Operation Crossroads", the atomic bomb test at Bikini, where she served as floating headquarters for congressional, scientific, and U.N. observers.