Carpellotti, originally designated DE-720, a Rudderow-classdestroyer escort, was re-designated as APD-136, a fast transport, on 17 July 1944, even before being laid down on 31 October 1944 at the Defoe Shipbuilding Company, in Bay City, Michigan. She was launched on 10 March 1945; sponsored by Mrs. S. Carpellotti. Builders trials before her pre-commissioning cruise were done in Lake Huron.
As it was completed too late for active participation in World War II, Carpellotti remained on active duty with the Atlantic Fleet, based in Norfolk, Virginia. Following a midshipman's cruise to English and French ports from 24 June through 2 August 1947, she was immobilized with a skeleton crew at Yorktown, Virginia, until 3 February 1948.
Resuming active service, Carpellotti operated from Norfolk on amphibious assault exercises along the United States East Coast and in the Caribbean. In the summer, she made midshipman cruises to European ports, and in 1948 made a good-will tour to the Persian Gulf. She also took part in North Atlantic Treaty Organization exercises: in 1952 in the first NATO amphibious "Operation Mainbrace"; and in 1955 and 1957 during her tours with the 6th Fleet in the Mediterranean.