The second ship with this name, it was launched on 4 March 1939 as Esso Seakay under a Maritime Commission contract (MC hull 3) by the Sun Shipbuilding and Dry Dock Company at Chester, Pennsylvania, sponsored by Mrs. Charles Kurz.

When American neutrality ended on 7 December 1941, Santee was carrying oil for a secret airdrome at NS Argentia, Newfoundland.

The ACV was fitted with such haste that workmen from Norfolk were still on board during her shakedown training and her decks were piled high with stores.

While the escort carrier was en route on 30 October, an SBD Dauntless being launched from a catapult dropped a 325 lb (147 kg) depth bomb onto the flight deck.

It rolled off the deck and detonated close to the port bow shaking the entire ship, carrying away the rangefinder and a searchlight base, and damaging radar antennas.

On 7 November, the escort carrier, with Rodman and Emmons and Monadnock, left the formation and, the following morning, took positions off Safi, French Morocco.

After disembarking passengers at Recife, she sailed to join Task Unit 23.1.6 (TU 23.1.6) at sea in tightening the noose on enemy merchant shipping and naval activity in the South Atlantic.

On 10 March, light cruiser Savannah and destroyer Eberle were investigating a cargo liner which had been spotted by Santee's aircraft and which had been tentatively identified as the Karin, a Dutch merchantman.

Santee's small task group left the convoy on 12 July with orders to operate independently against Nazi submarine concentrations south of the Azores.

After providing air cover for the battleship and her escorts for several days, Santee was ordered to the Bay of Biscay, where she engaged in anti-submarine work until the end of November.

From 22 to 28 December, the escort carrier packed her hangar and flight decks with P-38 Lightning fighter planes at Staten Island.

Sangamon, Suwannee, Chenango and Santee, all former oilers, swarmed out of Pearl Harbor with a flock of destroyers on 15 March, heading southwest.

After training exercises and the re-embarkment of her own planes at Manus, Santee got underway on 10 September and rendezvoused with TF 77 near Mapia Island.

At 07:36 on 25 October, Santee launched five Avengers and eight Wildcats for an attack against Japanese surface units some 120 mi (190 km) to the north.

After post repair trials at San Diego, the escort carrier headed toward Hawaii on 31 January 1945, and arrived at Pearl Harbor on 8 February.

For 42 consecutive dawns, Santee's aircraft winged over target sectors in the East China Sea, with daily returns to Okinawa itself for routine ground support.

Pulling out of the Okinawa area that day, Santee reached Leyte Gulf on 19 June, where minor repairs were made.

On 7 July, a tail hook broke on a landing aircraft, allowing it to clear all barriers, crash among parked planes, and cause a fire.

Santee received word of the cessation of the hostilities against Japan on 15 August and anchored in San Pedro Bay, Leyte, two days later.

On 4 September, while en route to Korea to support occupation forces there, Santee was ordered to northern Formosa to evacuate ex-prisoners of war.

The next day, Santee continued her role in "Operation Magic Carpet" by embarking 18 Marines bound for the west coast.

Santee was reclassified on 12 June 1955 as an escort helicopter aircraft carrier, CVHE-29, and struck from the Naval Vessel Register on 1 March 1959.