Following service aboard a cruiser, 1935-37, McCampbell applied for flight training and was accepted. He received his "wings of gold" in 1938 and was assigned to Fighting Squadron Four on the East Coast. Subsequently he became a landing signal officer and survived the sinking of USS Wasp (CV-7) off Guadalcanal in September 1942.

McCampbell formed VF-15 on 1 September 1943 and led the squadron before being assigned as Commander of Air Group Fifteen in February 1944 to September 1944. As Commander Air Group (CAG) 15, he was in charge of fighters, bombers, and torpedo bombers aboard the aircraft carrier USS Essex. From April to November 1944, his group saw six months of continuous combat and participated in two major air-sea battles, the First and Second Battles of the Philippine Sea. During the more than 20,000 hours of air combat operations before it returned to the United States for a rest period, Air Group 15 destroyed more enemy planes (315 airborne and 348 on the ground) and sank more enemy shipping than any other Air Group in the Pacific War. Air Group 15’s attacks on the Japanese in the Marianas and at Iwo Jima, Taiwan, and Okinawa were key to the success of the “island hopping” campaign.

In addition to his duties as commander of the “Fabled Fifteen,” then Commander McCampbell became the Navy’s “Ace of Aces” during the missions he flew in 1944. McCampbell flew three F6F Hellcats while aboard the Essex: an F6F-3 named The Minsi, an F6F-5 named Minsi II, and an F6F-5N named Minsi III (Bureau Number 70143), in which he scored the last 20 of his 34 kills.

On June 19, 1944, during the "Marianas Turkey Shoot," Cdr. McCampbell shot down seven Japanese aircraft, to become an "Ace in a day." On October 24, 1944, he repeated the feat, the only American airman to do so. McCampbell and his wingman attacked a Japanese force of 60 aircraft. McCampbell shot down nine, setting a single mission aerial combat record. When he landed his Grumman F6F Hellcat, his six machine guns had two rounds remaining and the plane had only enough fuel to keep it aloft for 10 more minutes. Cdr. McCampbell received the Medal of Honor for both actions, becoming the only fast carrier task force pilot to be so honored.

For his brilliant record in command of Air Group 15, McCampbell was awarded the Medal of Honor, the Navy Cross, the Silver Star Medal, Legion of Merit with Combat “V”, the Distinguished Flying Cross with two Gold Stars in lieu of the second and third awards, and the Air Medal.

Following World War II, McCampbell had several postings, including command of the carrier USS Bon Homme Richard (CVA-31) during the Korean War. He also served as the plans division chief of the Joint Chiefs of Staff.
Captain McCampbell retired from active duty in 1964. He died in 1996 and was interred at Arlington National Cemetery.