Frustrated in his efforts to become a fighter pilot because of a minor astigmatism discovered just before he was to report to NAS Pensacola, Florida for training, Frank B. Mormillo still enjoyed photographing airplanes. So, he turned instead to a career in photojournalism, eventually specializing in covering aviation, military and auto racing subjects, though he did photograph a variety of other subjects as well.

Over the years, in the course of his work as a photojournalist, Mormillo did get to fly in a wide variety of military aircraft with the United States Air Force, Navy Marine Corps, Army and Coast Guard, as well as with the British Royal Air Force. He even sailed on Navy and Coast Guard ships and operated in the field with Army and Marine Corps ground forces during realistic training exercises.

For over 35 years, Mormillo also covered all sorts of motor sports events, and was the track photographer at both the Riverside International raceway and the Ontario Motor Speedway in California until they closed. For 21 years, he also lectured on photography and photojournalism and operated photo lab facilities as a staff member at the college and university level.

Well known in the civilian warbird community, Mormillo has also been involved with the Planes of Fame Air Museum (now located at the Chino Airport, California) since 1957. His college senior internship was as a public relations specialist with the museum and, since 1980, he has been the museum's media relations coordinator, in which capacity he also serves as a photographer and historian.