A destroyer commander during World War II, he was present during the attack on Pearl Harbor and later received the Navy Cross for his tactical acumen during the Guadalcanal Campaign.

[1] After graduating from Fredericktown High School he briefly attended Denison University before entering the United States Naval Academy.

[1] During the Japanese attack on Pearl Harbor on December 7, 1941, most of the Agnew family – Dwight, his brother Henry, and both of their sisters and brothers-in-law (the latter who were also Navy officers) – were stationed in Hawaii.

[3][4] The following week, on December 14, Agnew led the Trever in the rescue of the crew and passengers of the torpedoed Norwegian freighter MS Høegh Merchant.

[1] According to his citation: ... his Unit was attacked by a force of three Japanese destroyers and during the ensuing battle he fought his ships with such brilliant success that none received serious damage and there was only small loss of personnel, while his vessels inflicted several hits on one enemy destroyer, setting it afire..."In 1943 he was transferred to San Francisco, California, to oversee the outfitting of the new USS Heermann, subsequently commanding that ship during engagements in the Pacific for which he received the Bronze Star.

[1] Following World War II, Agnew held a variety of staff assignments in the Navy – including as the naval representative to the Joint American Military Mission for Aid to Turkey – and, from January 1952 to February 1953, was commanding officer of Destroyer Squadron 10 in the United States Atlantic Fleet.