Upon completion of sea trials and outfitting, Guadalcanal departedPhiladelphia to join the Amphibious Forces, U.S. Atlantic Fleet. One of a new class of ships designed from the keel up to embark, transport, and land assault marines by means of helicopters, she lent new strength and flexibility to amphibious operations. After departing Norfolk 23 October 1963 for 6 weeks shakedown training at Guantanamo Bay, Cuba, Guadalcanal steamed to Onslow Beach,North Carolina, 6 December for practice amphibious landings. She then carried on training and readiness operations with the Atlantic Fleet, based in Norfolk until departing for Panama 11 February 1964. Following 2 months on station as flagship for Commander PhibRon 12 with the 12 Marine Expeditionary Unit embarked and ready to land anywhere needed. Guadalcanal entered Philadelphia Naval Shipyard 26 May, but was deployed again 7 October as a unit of Operation "Steel Pike 1", a NATO landing exercise on the beaches of southern Spain.
Highlights of her career included 21 July 1966 when she recoveredGemini X astronauts after their spacecraft landed in the Atlantic east of Cape Kennedy, and 13 March 1969 when she recovered Apollo 9off the Bahamas. In October 1985 the ship logged its 100,000th aircraft landing. In 1987 the Guadalcanal was leading minesweepingoperations in the Persian Gulf when it encountered the Iran Ajarlaying mines in the shipping lanes. Helicopters from the Guadalcanal attacked the ship; troops from the Guadalcanal boarded and captured the ship. (Iran Ajar was the second enemy warship captured on the high seas by the U.S. Navy since 1815; the first was the German submarine U-505 captured in 1944 by the first USSGuadalcanal, an escort carrier.) This Guadalcanal also provided the Marines for the first wave of Operation Provide Comfort, the Kurdishrelief operations in Northern Iraq immediately following the Persian Gulf War in 1991. She was decommissioned in 1994, and stored as part of the James River Reserve Fleet until she was used as a target and sunk in the Virginia Capes area on May 19, 2005