Sangamon earned eight battle stars during World War II. Her three air groups were each awarded the Presidential Unit Citation.
USS Sangamon (CVE-26) was an escort carrier converted from an oiler, the second ship to carry her name. She was one of 12 Cimarron class oilers built on a joint Navy-Maritime Commission design later duplicated by the T3-S2-A1 type. Sangamon was laid down as Esso Trenton (MC hull 7) on 13 March 1939 by the Federal Shipbuilding and Dry Dock Company, Kearny, New Jersey; launched on 4 November 1939, sponsored by Mrs. Clara Esselborn; operated by Standard Oil of New Jersey on runs from gulf coast ports to the east coast; and acquired by the United States Navy on 22 October 1940. Renamed Sangamon and designated a fleet oiler, AO-28, she was commissioned on 23 October 1940, with Commander J. H. Duncan in command.
After service off the west coast and in Hawaiian waters, Sangamon shifted to the Atlantic Fleet in the spring of 1941, and through the Neutrality Patrol period, carried fuel from the gulf coast oil ports to bases on the east coast, in Iceland. On 7 December 1941, when the U.S. entered World War II, she was at Naval Station Argentia, Newfoundland, offloading her liquid cargo. Within the week, she started south again to renew her schedule on a tighter time frame.
In early 1942, she was designated for conversion to an auxiliary aircraft carrier. On 11 February, she arrived in Hampton Roads. Three days later, she was reclassified AVG-26; and on 25 February, she was decommissioned and conversion was begun at the Norfolk Navy Yard.
During the spring and summer, the need for auxiliary carriers, later called escort carriers, increased. Work on Sangamon, three other Cimarron-class oilers, and 20 C-3 merchant hulls was continued and sped up. In August, Sangamon — the first of her class of escort carriers – was ready. Her conversion had added a flight deck 502 ft (153 m) long and 81 ft (25 m) wide, elevators, a hangar deck, an aircraft catapult, sonar gear, aircraft ordnance magazines, workshops, and stowage space for aviation spares. Her accommodations had been enlarged to house her increased complement and embarked aviation personnel, and her armament had been changed to two 5"/127mm guns, eight 40 mm guns, and twelve 20 mm cannons to increase her anti-aircraft defense. On 20 August, she was redesignated ACV-26; and five days later, she was recommissioned, with Captain C. W. Wieber in command.
Sangamon and her three sister T3 conversions were considered very successful escort-carrier designs, larger and more stable than the smaller C3-derived Bogue class; additionally, they retained substantial oil bunkerage, useful in refueling destroyers in company. The late-war purpose-built Commencement Bay-class escort carriers were derived from the Sangamons.
Shakedown in Chesapeake Bay and off Bermuda followed a return to the yard for repair and improvements to her ventilation system, and on 25 October she sailed east with Task Force 34 (TF 34) to provide air cover for Operation Torch, the invasion of North Africa. Assigned to the Northern Support Force, she arrived off Port Lyautey on 8 November. Prior to and during the landings, and subsequent action, her air group, Composite Squadron 26 (VC-26) flew combat air patrol (CAP), anti-submarine patrol (ASP), and ground support missions. At mid-month, she got underway to return to Norfolk, Virginia, whence, after repairs, she sailed for Panama and the Pacific.
By mid-January 1943, Sangamon had arrived at Éfaté, New Hebrides. As a unit of Carrier Division 22 (CarDiv 22), she operated in the New Caledonia—New Hebrides—Solomon Islands area for the next eight months. With Suwannee and Chenango, she provided protection for resupply convoys en route to Guadalcanal and for the assault forces moving on the Russell Islands.
Captain E. P. Moore took over as captain on 5 April 1943. Redesignated CVE-26 on 15 July 1943, Sangamon shifted her base of operations from Efate to Espiritu Santo in August, and, in