Launched in May 1943, and commissioned in September, she served as a transport carrier, ferrying aircraft to bases in Europe, Africa, and Asia.

She was powered with two Uniflow reciprocating steam engines, which drove two shafts, providing 9,000 horsepower (6,700 kW), thus enabling her to make 19 knots (35 km/h; 22 mph).

By the end of the war, Casablanca-class carriers had been modified to carry thirty 20–mm cannons, and the amount of 40–mm guns had been doubled to sixteen, by putting them into twin mounts.

[4] The escort carrier was laid down on 28 December 1942, under a Maritime Commission contract, MC hull 1096, by Kaiser Shipbuilding Company, Vancouver, Washington.

She was launched on 26 May 1943; sponsored by Mrs. James McDonald; transferred to the United States Navy and commissioned on 13 September 1943, with Captain William Lehigh Rees in command.

[1][5] Upon being commissioned, Mission Bay underwent a shakedown cruise down the West Coast to San Diego.

[5] Her next cruise started on 20 February, when she departed New York City, transporting Army planes and crew, bound for India.

On 28 May, she departed New York again, ferrying aircraft along with Kasaan Bay and Tulagi, round trip to Casablanca.

After refueling at Dakar, French West Africa on 20 September, she began antisubmarine operations, which lasted throughout the month of November.

She was then ordered to sail to Gibraltar, where she would meet the heavy cruiser Quincy which was carrying President Franklin D. Roosevelt and his entourage back from the Yalta Conference.

On 30 November 1949, she was moved up to the Bayonne Naval Supply Depot, New Jersey, where she lay until she was struck from the Navy list on 1 September 1958.