Brazos was laid down at the Boston Navy Yard; launched 1 May 1919; sponsored by Miss Catherine Rush; and commissioned 1 October 1919.

As a tanker attached to the Train, Scouting Fleet, Brazos carried fuel oil and stores along the east coast of the United States and in the Caribbean.

In 1922 she served temporarily with the U. S. Naval Detachment in Turkish waters and transferred personnel and remains of the war dead from Marseille to the United States.

Except for brief periods in reduced commission for overhaul and repair, the succeeding years saw no variation in the vital duties performed by Brazos.

On 29 March 1945 she arrived at Okinawa to furnish logistics support for the invasion fleet, after having made several brief stops in the southwestern Pacific.