Too smart for his/her/its own good (British clever being roughly equivalent to U.S. smart). OED notes the first use of … by half formulation in Sheridan’s 1780 School for Scandal–“Oh, he’s too moral by half”–and of too clever by half in 1858. As the Punch cartoon suggests, it quickly became a popular catchphrase and remains so.
Google Ngram shows an interesting (and common) pattern in U.S. and Britain. British use peaks in about 1980, then declines. American use has roughly doubled since 1950. Currently, use is about equal in both countries.