SS Sierra was constructed as a commercial passenger ship in 1900 by William Cramp and Sons in Philadelphia, Pennsylvania. The U.S. Navy acquired her from the John D. Spreckel Brothers Company in San Francisco, California, on 27 May 1918 for use as a troop transport during World War I and assigned her the identification number 1634. After conversion work was complete, she was commissioned as USS Sierra (ID-1634) on 1 July 1918.