He graduated from the U.S. Naval Academy in 1944 with a Naval Science degree. He was commissioned as an ensign and reported to the destroyerUSS Caperton. While serving aboard USS Caperton, he participated in campaigns in the Philippines, Formosa and Okinawa. After graduation from flight training in 1947, he was assigned to Fighting Squadron Twenty Able which was later redesignated Fighter Squadron 192.
Petersen served as Commanding Officer of Fighter Squadron 154 prior to being assigned to the office of Director, Division of Naval Reactors, Atomic Energy Commission for Nuclear Power Training. He reported to the aircraft carrierUSS Enterprise in January 1964 and served as Executive Officer until April 1966. He was awarded the Bronze Star for duty during Enterprise's first combat tour in Vietnam. In November 1967, he assumed command of USS Bexar in the Pacific Fleet Amphibious Forces. Following an eight-month deployment with the United States Seventh Fleet Amphibious Forces in the Western Pacific, he was awarded the Navy Commendation Medal with Combat V. He then served as Commanding Officer of USS Enterprise (July 8, 1969 – December 3, 1971). He was then assigned duties as an Assistant to the Director of Naval Program Planning in the office of the Chief of Naval Operations. In 1974, he went on to command Combined Task Force 60 (CTF-60) based at Athens, Greece.[6] In 1975 he came back to the Pentagon to head the Naval Air Operations office. He then headed the Naval Air Systems Command, from which he retired in 1980.
Petersen married June Berkshire on February 2, 1946. They had three children: Lynn Elizabeth, Nels Christian, and Forrest Dean. June died on May 8, 1977.
He subsequently married Jean Baldwin on June 17, 1978; she had a son, Preston. She died in 2005.