Sandusky, originally classified as a "patrol gunboat," PG-162, was reclassified as a "patrol frigate," PF-54 on 15 April 1943. Laid down on 8 July 1943 under a Maritime Commission contract by Froemming Brothers, Inc., in Milwaukee, Wisconsin, she was launched on 5 October 1943, sponsored by Miss Mabel Apel, and commissioned on 18 April 1944 at New Orleans, Louisiana, with Lieutenant Commander T. R. Sargent, III, USCG, in command.