Following trial runs in Long Island Sound, Blue Ridge departed New York on 8 October 1943, to train in the Chesapeake Bay Area out of Norfolk, Virginia.

After transit of the Panama Canal, Blue Ridge called at the Society, New Caledonia and Fiji Islands, en route to Brisbane, Australia, arriving on 16 December 1943.

She pulled out of Brisbane three days later for Milne Bay, New Guinea where 24 December 1943, she became the flagship of Rear Admiral Daniel E. Barbey, USN, Commander Seventh Amphibious Force.

On that day, Blue Ridge left Hollandia (currently known as Jayapura) as the flagship of Rear Admiral Barbey's Northern Attack Force bound for the liberation of the Philippine Islands.

She served as a command ship for troops storming the beaches at Leyte the morning of 20 October, and continued in support of the amphibious assault landings for six days.

She stood out of San Pedro Bay in the night of 26 October 1944 to stage at ports of New Guinea in preparation for the liberation landings to be made at Lingayen.

An aerial snooper was driven off by gunfire on 2 January 1945 and covering escort carrier aircraft shot down a bomber twenty miles out from her formation the following day.

On the afternoon of 5 January an enemy submarine fired on the covering group, ten miles ahead, and was forced to surface and rammed by destroyer Dashiell.

During the initial landings, three air attacks came close enough to be a threat to Blue Ridge, but veered off in the face of heavy anti-suicide swimmers and small fast suicide boats.

Two days later, Blue Ridge was underway for Saipan and then to Pearl Harbor when she became the flagship of Rear Admiral Jerauld Wright, Commander Amphibious Group Five on 30 June 1945.

Here the ship completed embarking general and flag officers of the Army, Navy and Marine Corps along with United Nations officials for transportation to Bikini Atoll to observe Atomic Bomb Tests.

Thereafter, she called at Ponape and Truk in the Caroline Islands, then proceeded to Kwajalein where, on 23 July, Blue Ridge became the flagship of Rear Admiral C. C. Glover.