Serpens was laid down on 10 March 1943 as the liberty ship SS Benjamin N. Cardozo (MCE hull 739) by California Shipbuilding Corporation, Wilmington, California, under a Maritime Commission contract; launched on 5 April 1943, sponsored by Mrs. H.P. Needham; transferred to the Navy on 19 April 1943, renamed Serpens and designated AK-97; and commissioned at San Diego on 28 May 1943, Lt. Comdr. M.J. Johnson, USCGR, in command.