Was there a Kilroy during World War II?

Kilroy was the hero of graffiti scrawled by countless U.S. servicemen during World War II, proclaiming “Kilroy was here,” but he may never have existed in person.

Sergeant Francis J. Kilroy of the U.S. Air Corps and James J. Kilroy, an inspector in a Massachusetts shipyard, have both been suggested as the namesake of the phrase, but hard evidence is lacking.