Nelson John Allen was born in Duluth, Minnesota, on 14 April 1916, son of John Allen and Mabel (Nelson) Allen. He attended Duluth High School and in 1935 entered the US Naval Academy, Annapolis, Maryland, upon appointment from his native state. Graduated and commissioned Ensign on 1 June 1939, he was promoted to Lieutenant (junior grade), to rank from 1 November 1941, Lieutenant, to date from 1 June 1942 and Lieutenant Commander (posthumous), to date from 12 April 1944.
Following graduation from the Naval Academy in 1939, he joined USS Astoria in which he served for three months. He next had fitting out duty in USS Biddle at the Navy Yard, Philadelphia, and reported on board that destroyer upon her commissioning, 16 October 1939. During December 1940 he assisted in the fitting out of USS Gwin Navy Yard, Boston, Massachusetts, but was detached before the Gwin was put into commission for submarine training at the Submarine Base, New London, Connecticut.
Ordered in April 1941 to Submarine Division FIVE, Asiatic Fleet, he subsequently had duty on board USS S-41 and was serving in that assignment when the United States entered World War II, 8 December 1941. He received a Letter of Commendation, with authorization to wear the Commendation Ribbon, from the Commander in Chief, US Pacific Fleet. The citation follows:
"For meritorious conduct...in the USS S-41 during the Fourth War Patrols of that vessel in the Solomon Islands Area from August 7, 1942 to September 3, 1942. As diving Officer, his careful and precise control of depth was of invaluable assistance to his commanding officer in conducting successful attacks, which resulted in the sinking of a 1,500 ton enemy submarine and damage to other ships of a convoy. His coolness and high devotion to duty contributed directly to the success of his vessel in evading enemy countermeasures."
During June and July 1943 he had temporary duty with the Submarine Force, US Pacific Fleet and Submarine Division TWENTY ONE and on 8 July, joined the submarine Sculpin, participating in two war patrols (the eighth and ninth). On the eighth war patrol, she was credited with sinking a freighter transport. On her ninth war patrol the Sculpin was severely damaged on 19 November 1943, north-east of Truk by depth charges from an enemy destroyer. Forced to surface, she fought the enemy vessel with her guns until she was badly holed and practically all of her gun crew on deck was killed. Impossible to fight further her vents were opened and she was sunk.
"For meritorious service while attached to the USS SCULPIN during the Ninth War Patrol of that vessel in action against enemy Japanese forces in the Truk Island Area, November 19, 1943..." he was posthumously awarded the Bronze Star Medal with Combat "V." The citation continues in part: "After his ship had been severely damaged and forced to the surface during a terrific enemy depth charge attack, (he) gallantly manned his battle station despite overwhelming opposition resolutely carrying out his duties until he fell, mortally wounded by enemy fire...He gallantly gave his life for his country."
In addition to the Bronze Star Medal with Combat "V," and the Commendation Ribbon also with "V," Lieutenant Commander Allen was entitled to the Purple Heart Medal; the Army Distinguished Unit Badge; the American Defense Service Medal, Fleet Clasp; the Asiatic-Pacific Campaign Medal with star; the World War II Victory Medal; and the Philippine Defense Ribbon.