She was laid down as Kanalku Bay under Maritime Commission contract by Kaiser Co., Inc., Vancouver, Washington on 15 September 1943; renamed Marcus Island on 6 November 1943; launched on 16 December 1943; sponsored by Mrs. S. L. La Hache; acquired by the Navy on 26 January 1944; and commissioned at Astoria, Oregon on 26 January 1944, Captain Charles F. Greber in command.