The last supposedly ordinary person to become President was Harry Truman... and he proves to have been extraordinary. He was smart enough to make few mistakes, and that is often the difference now between being a bare graduate of high school and a PhD.
He was a senator from MO, so he was not an "everyday person"
Depends on just what we're defining as an "everyday person" here, because at heart, he was really just a haberdasher whose sense of community service (rather than something like pure personal ambition) saw him wind up in the Oval.
