Du Page was the first ship of that name, for a county in Illinois. Ingalls launched her at Pascagoula on 19 December 1942 as Sea Hound, and Mrs. Leigh R. Sanford sponsored her. She was AP-86 until 1 February 1943, when she became APA-41 in the Bayfield class. Commander C. Allen had her in a ferry commission dated 28 February 1943. She was decommissioned on 17 March for conversion at Todd-Erie Basin Dry Docks in Brooklyn. Captain G. M. Wauchope, USNR, commissioned her on 1 September 1943.
Norfolk to San Diego ended on 2 November 1943, and she served as flagship of a transport division while the ships trained. On 13 January 1944 she sailed carrying Marines for the Kwajalein assault landings and stayed from 31 January to 6 February. Funafuti, in the Ellice Islands, lay on the way to Guadalcanal, where she arrived on 18 February. Based there, she helped move troops around the Solomons, put assault troops onto Emirau on 11 April, Cape Gloucester, on New Britain, was a support landing that ran from 28 April into 1 May. Guam was the next invasion. She sailed on 3 June, and the troops went ashore across 21 to 26 July. Casualties were carried out to Eniwetok. Drills off Espiritu Santo followed. Guadalcanal on 27 August was for stores, a landing-craft overhaul, and Palau training.
The sortie from Guadalcanal was on 8 September. A week later she landed troops in the Peleliu assault. For twelve days she remained, giving logistic help to landing craft and to small patrol vessels. Three of her boats were lost and one man was killed. Hollandia on 30 September was the pause before the Philippines. She carried Army troops into the initial Leyte landings on 20 October, left at once for reinforcements at Hollandia, and put those men into the support landings on 14 November. Rehearsal landings in New Guinea came next. From Aitape on 28 December she sailed for Lingayen Gulf, The San Fabian beaches took her troops on 9 January 1945. She then took casualties off that beach and off other ships.
On the evening of 10 January, as she prepared to leave, enemy planes attacked. Antiaircraft fire was heavy and still did not stop a kamikaze, which crashed to port, damaged her severely, and set fires that kept breaking out until morning. Thirty-five men were killed. The wounded numbered 136. An escorting destroyer recovered five men who had been thrown overboard, several hours afterward. She kept her duty as guide ship and reached Leyte three days later, transferred the wounded, and took emergency repairs. Troops went ashore at Zambales, Luzon, on 29 January. She left San Pedro Bay on 11 February, embarked Marines at Manus and Pearl Harbor on the way, and arrived at San Francisco on 10 March for overhaul and repair of that damage.
From Alameda on 14 May she went to Seattle for troops bound to Pearl Harbor, then to Eniwetok for amphibious exercises. Ulithi gave her troops and cargo for Okinawa. She delivered them on 5 July. After three days she left with Marines who had already been in combat. Guam came first, then Eniwetok, and San Francisco on 28 July. Minor alterations followed. Designated flagship of Transport Division 63, Army Air Force men were the passengers when she sailed on 12 August. She put them ashore at San Pedro Bay, Leyte, on 5 September. On 1 October she left Lingayen Gulf with occupation troops for Japan and landed them at Nagoya on 26 October. Magic Carpet orders came three days later. Veterans rode her home on a pair of trips that began at Guam and ended on the west coast. Portland, Oregon, on 5 January 1946 closed that work. Two weeks after that she headed east and reached New York on 7 February. She was decommissioned on 28 March 1946. The War Shipping Administration took her for disposal on 27 June 1946. Six battle stars were awarded.