Keystone State was laid down on 23 January 1965, as the combination breakbulk-container ship SS President Harrison, ON 502569, IMO 6605022, a Maritime Administration type (C4-S-1qa) hull, under MARAD contract (MA 166).

Built by National Steel and Shipbuilding Co., San Diego, CA, hull no.

339, she was launched 10 February 1965, and delivered to MARAD on 25 April 1966, for service with American President Lines.

She was converted to a MARAD type (C6-S-1qc) container ship, 16 February 1973, and continued to be operated by APL until delivered to the Maritime Administration, 19 July 1982, for lay up in the National Defense Reserve Fleet (NDRF), Suisun Bay, Benicia, CA, and was later transferred to NDRF James River, Lee Hall, VA., 11 September 1982.

[1][2] She was placed in service as SS Keystone State (ACS-1) 7 May 1984, and assigned to the Military Sealift Command (MSC) Ready Reserve Force (RRF).