Samuel Johnston was laid down on 14 April 1942, under a Maritime Commission (MARCOM) contract, MCE hull 46, by the Bethlehem-Fairfield Shipyard, Baltimore, Maryland; she was sponsored by Miss Elaine Trimble, the daughter of Colonel South Trimble Jr., the Solicitor for the Department of Commerce, and was launched on 14 June 1942.
She was allocated to Eastern Steamship Co., on 30 June 1942. On 27 September 1947, she was laid up in the National Defense Reserve Fleet, Wilmington, North Carolina. She was sold for scrapping on 24 March 1957, to Union Minerals & Alloys Corp., for $48,770. She was removed from the fleet, 26 April 1967.