Ed Dierling was born in 1943 in New Jersey. He enlisted in the U.S. Army on November 12, 1965, and completed basic training at Fort Dix, New Jersey, in February 1966. Pvt Dierling next attended Military Intelligence Specialist training at Fort Holabird, Maryland, from February to June 1966, followed by service as a military intelligence specialist with the 115th Military Intelligence Group at the Presidio of San Francisco, California, and in Portland, Oregon, from June 1966 to July 1967. He then attended Vietnamese Language training at the Defense Language Institute Support Command at Fort Bliss, Texas, from July to September 1967, before serving as a military intelligence specialist with the 135th Military Intelligence Group in South Vietnam from November 1967 until he was captured and taken as a Prisoner of War on February 3, 1968. After 21 days in captivity, Sgt Dierling managed to escape from his captors on February 23, 1968, and made it back to friendly lines. He returned to the United States in March 1968, and then served as a Senior Counterintelligence Agent with the 115th Military Intelligence Group in Portland, Oregon, from March 1968 until he left active duty on November 8, 1968.

His Silver Star Citation reads:

For gallantry in action while engaged in military operations involving conflict with an armed hostile force in the Republic of Vietnam: Sergeant Dierling distinguished himself by exceptionally valorous actions form 30 January to 23 February 1968 during the communist Tet offensive against the city of Hue. North Vietnamese Army forces infiltrated the city and directed a series of coordinated attacks against military housing and installations. Enemy elements surrounded the area he and his team occupied, and Sergeant Dierling immediately helped destroy vital intelligence documents in the team's possession. After moving to a more tenable position in a nearby house, he organized defenses and distributed weapons and ammunition. The enemy delivered ravaging machine gun, mortar and rifle fire on his small unit, and he fought furiously to repel the attacks. Firing deadly barrages into the advancing North Vietnamese troops, his team succeeded in repulsing several fanatical assaults which reached point blank range. Reinforcements were unable to reach Sergeant Dierling and his men, and the North Vietnamese forces captured them after forty-eight hours of savage fighting. They were taken to an enemy camp outside the city and held captive there for nineteen days. Throughout the period, Sergeant Dierling remained alert for escape possibilities despite weariness from lack of food and sleep. On 19 February, he and twenty other prisoners began a march to another camp. When a guard became careless after four days of travel, he made a fearless dash into the jungle and fought through the dense vegetation to reach friendly lines iwth highly valuable intelligence information. Sergeant Dierling's gallantry in action was in keeping with the highest traditions of the military service and reflects great credit upon himself, his unit, and the United States Army.