Dear Cecil,
About 20 years ago or more I read another version of the Kilroy origin, and I’ve seen a similar but shorter version in print years later.
The general outline of the story is this:
A steel fabricating company owned by a man named Kilroy wins a contract to supply war materiel during WWII including steel building components. A rumor gets started that Kilroy’s company is shorting the government and profiteering. Kilroy, a more patriotic guy than most, tells his foremen to start stencilling the company name on everything that goes out of the factory, everything. GIs landing in North Africa see all this materiel lying around with Kilroy’s name all over it and wonder who the hell Kilroy is. When they get to the front, they decide to have a little fun and start putting Kilroy’s name wherever they go, eventually adding the ‘was here’ part and the drawing.
Hey, who was the original Murphy in Murphy's Law?
Slainte! Max
Original Article:
http://www.straightdope.com/mailbag/mkilroy.html