Following over a year at the Marine Corps Basic School in Philadelphia as a student aviator, Lieutenant Elrod was ordered to the Naval Air Station Pensacola, Florida.

In July 1938, Elrod was ordered to a squadron in San Diego and served as their material, parachute, and personnel officer until January 1941, when he was detached to the Hawaiian area.

Engaging vastly superior forces of enemy bombers and warships on 9 and 12 December, Captain Elrod shot down two of a flight of twenty-two hostile planes and, executing repeated bombing and strafing runs at extremely low altitude and close range, succeeded in inflicting deadly damage upon a large Japanese vessel, thereby sinking the first major warship to be destroyed by small caliber bombs delivered from a fighter-type aircraft.

When his plane was disabled by hostile fire and no other ships were operative, Captain Elrod assumed command of one flank of the line set up in defiance of the enemy landing and conducting a brilliant defense, enabled his men to hold their positions and repulse determined Japanese attacks, repeatedly proceeding through intense hostile fusillades to provide covering fire for unarmed ammunition carriers.

Responsible in a large measure of the strength of his sector's gallant resistance, on 23 December, Captain Elrod led his men with bold aggressiveness until he fell, mortally wounded.

His superb skill as a pilot, daring leadership and unswerving devotion to duty distinguished him among the defenders of Wake Island, and his valiant conduct reflects the highest credit upon himself and the United States Naval Service.