[1] Fort Marion was launched on 22 May 1945 by Gulf Shipbuilding Corp., Chickasaw, Alabama, sponsored by Mrs. Louise S. Dodson; and commissioned on 29 January 1946.

Upon the outbreak of the Korean War, Fort Marion sailed for action 12 July 1950, and arrived at Pusan with Marines and their equipment 2 August.

On 12 September, at Pusan, Fort Marion embarked men of the 3rd Battalion, 5th Marines and three LSUs, carrying ten tanks, for the invasion of Inchon.

Fort Marion, with 250 men of the British Royal Marines' 41 Commando battalion, and Begor (APD-127) with a UDT detachment, set sail for Sorye Dong, eight miles south of Sŏngjin, with a supporting force composed of Saint Paul (CA-73), two destroyers, and six minesweepers.

Despite fog and an unsuitable landing zone, the commandos blew up about 100 yards of railroad, and were then successfully reembarked, although they found that airstrikes by Task Force 77 had already made the railway inoperable.

Back in San Diego 19 August 1954, she sailed later that year to the Hawaiian Islands for exercises, and in May 1955 took part in Operation Wigwam, the experimental detonation of an underwater atomic explosion.

Fort Marion spent much of 1960 in an extensive modernization overhaul which added many useful years to her expected span of service, and on 22 November sailed for Far Eastern duty once more.