IMO "smart" is more of a social role than anything else. There's a specific sort of behavior that you have to do in order for people to think that you're "smart". Like, take George W. Bush for example - he's about two standard deviations above average in intelligence, but his public-facing persona lines up much better with "regular guy" and so people misunderestimate him.

You can find similar examples from all sorts of public figures - when you dig into them, there's way more there than their persona suggests. Kanye West, Lady Gaga, Marilyn Manson, Dolph Lundgren, and more.