USS Custer (AP-85) was launched as SS Sea Eagle 6 November 1942 by Ingalls Shipbuilding Co., Pascagoula, Mississippi, under a U.S. Maritime Commission contract; sponsored by Mrs. L. S. Border.

Custer moved to the Bethlehem Steel Shipyard, Hoboken, New Jersey, to be converted into, and armed as an attack transport - the period of conversion consumed 159 days.

Held in reserve during the invasion of Kwajalein, she landed her troops on Eniwetok on 19 February and embarked casualties, with whom she returned to Pearl Harbor 6 March.

After sailing to embark men and cargo at San Francisco, California, Custer joined in amphibious training exercises in the Hawaiian Islands, and arrived at Kwajalein 9 June.

She put to sea 2 days later for the assaults on Saipan and later on Guam, transporting troops and evacuating casualties to Eniwetok until her return to Pearl Harbor 7 August.

She sailed to transport troops from Manila to Sasebo, Japan, then embarked homeward bound servicemen for San Pedro, California, arriving 21 November.