Joe Mossman was born on June 9, 1939, in Upper Darby, Pennsylvania. He enlisted in the Aviation Cadet Program of the U.S. Navy on September 9, 1961, was commissioned an Ensign on February 16, 1962, and was designated a Naval Aviator in June 1963. Ens Mossman then completed A-4 Skyhawk Replacement Air Group training with VA-43 at NAS Oceana, Virginia, from August 1963 to March 1964, followed by service as an A-4 pilot with VA-72 at NAS Oceana from March 1964 to May 1965, and then deployed aboard the aircraft carrier USS Independence (CVA-62) from May 1965 until he was killed in action while flying a combat mission over North Vietnam on September 13, 1965. Joe Mossman's remains have never been returned to the United States.

His Distinguished Flying Cross Citation reads:

For meritorious achievement in aerial flight as the pilot of an A4E aircraft while serving with Attack Squadron SEVENTY TWO, embarked in USS INDEPENDENCE (CVA-62) during missions in support of combat operations in Southeast Asia against the insurgent communist guerrilla forces. From 1 July to 13 September 1965 Lieutenant (junior grade) MOSSMAN successfully completed FIFTY-SIX combat missions contributing materially to the success of United States efforts in Southeast Asia. He continuously demonstrated superb airmanship, courage, and devotion to duty in the face of enemy fire and hazardous flying conditions. His heroic performance throughout was an inspiration to his shipmates and was in keeping with the highest traditions of the United States Naval Service.