Grumium was laid down under a Maritime Commission (MARCOM) contract, MCE hull 443, on 12 November 1942, as the liberty ship SS William G. McAdoo, by the Permanente Metals Corporation, Yard No.

[3] At San Francisco Grumium was transferred to the direct control of commander, Naval Air Forces, Pacific Fleet, and underwent conversion to an aviation support ship.

She was redesignated IX-174, 20 June 1944, and 2 days later was underway for Pearl Harbor once more, to supply American fast carrier aircraft, then increasing greatly in numbers.

Arriving 19 July, the ship transferred supplies to aircraft groups until early September, then returned to Pearl Harbor.

There she supplied carrier forces making the supporting strikes for the Philippine campaign, as America’s great island offensive gained momentum.

Grumium remained there during and after the final operations of the war providing vital supplies until departing for the Hawaiian Islands 12 October.

[3] The ship was subsequently laid up in the National Defense Reserve Fleet, James River Group, Lee Hall, Virginia.