On 30 September 1937, Brock was assigned to the staff of the Commander, Carrier Division 2, Rear Admiral Charles Adams Blakely.

Promoted to aviation ordnanceman third class on 16 February 1938, Brock was transferred to Torpedo Squadron 6 soon afterward, on 15 April 1938.

In the course of the flight toward the Imperial Japanese Navy's "Mobile Force" of aircraft carriers, the fighters, dive bombers and torpedo planes of Enterprise's attack group became separated from one another.

Thus unable to carry out a coordinated attack as doctrine dictated, Torpedo Squadron 6 went in unsupported by fighters or dive bombers, and 10 of its fourteen planes were shot down.

She reached San Diego, California, on 23 April 1945, but remained there only 18 hours before putting to sea for Hawaii with United States Marine Corps replacements embarked.

Pausing there for four days, Brock joined company with Kane once more and departed on 7 June 1945 to escort a convoy to the Ryukyu Islands.

On the evening of 23 June 1945, orders sent Brock 20 nautical miles (37 kilometers) to seaward to rescue a downed pilot, who turned out to be First Lieutenant Gustave T. Broberg, USMCR, a former all-American basketball player from Dartmouth College.

Brock's starboard 20-millimeter and 40-millimeter guns aft opened fire at point-blank range, "positively and unmistakably"[1] hitting the plane, which observers identified as a Mitsubishi J2M "Jack" single-engine Imperial Japanese Navy fighter.

Arriving in San Pedro Bay at Leyte on 6 July 1945, Brock reported for duty with the Philippine Sea Frontier's forces and carried out local patrols for the remainder of World War II, which ended on 15 August 1945.

Winding up her Philippine Sea Frontier duty, Brock set course for Hollandia, Dutch New Guinea, on 20 August 1945 and crossed the equator for the first time on 23 August 1945; in the traditional "Neptune Ceremonies," her 33 "shellbacks" duly initiated nearly 200 "pollywogs," including the commanding officer and 10 of the 12 officers on board.

Along with other work, Brock received a coat of peacetime gray paint over the "green dragon" camouflage that had become standard for high-speed transports.

At that point, Brock broke her homeward-bound pennant and set course for the United States in company with high-speed transport USS John Q. Roberts (APD-94).

On 1 June 1960, her name was stricken from the Navy List, and she was sold to the government of Colombia in January 1962 for use as a floating power plant.