Topics: Stories from Slate - Slate Magazine
Kilroy was here is an American popular culture and a meme expression that became popular during World War II; it is typically seen in graffiti. Its origins are debated, but the phrase and the distinctive accompanying doodle became associated with GIs in the 1940s – a bald-headed man (sometimes depicted as having a few hairs) with a prominent nose peeking over a wall with the fingers of each hand clutching the wall.
"Kilroy" was the American equivalent of the Australian Foo was here which originated during World War I and later became popular among school children.
" Mr Chad " or just " Chad " was the version that became popular in the United Kingdom. The character of Chad may have been derived from a British cartoonist in 1938, possibly pre-dating "Kilroy was here".