She was named for The Cabildo in New Orleans, the old town hall and now a historical museum, where the formal transfer of the Louisiana Territory from France to the United States took place.

Laden with men of the Army Engineers, she arrived at Manila on 3 October, then sailed for Japan, where she acted as receiving and repair ship at Sasebo and Yokosuka until 19 April 1946.

Recommissioned at San Diego on 5 October 1950, she took part in atomic weapons tests in the Marshalls — "Operation Greenhouse" — in which she was one of the first ships to become radioactive.

While with this group in April off Wonsan, Cabildo received a direct hit from a shore battery, suffered a few casualties, but was able to continue her mission.

In 1955 she was fitted with mezzanine and helicopter decks, and from that time operated extensively with Marine units in developing the vertical envelopment concept of amphibious warfare.

Clearing San Diego on 11 February 1959, she carried craft and an underwater demolition team detachment to the Aleutians before continuing to Japan.

In the spring of 1963, the ship sailed back to the West Coast and her home port of Long Beach via the Panama Canal after serving as part of the Navy's Cuban Missile Blockade.