(history) An immigrant from the Northern to the Southern States after the American Civil War of 1861–5, especially one who went South to gain political influence.
(by extension) One who comes to a place or organisation with which they have no previous connection with the sole or primary aim of personal gain, especially political or financial gain.
He's just a carpetbagger who was surprised to find that Southerns are not like the cast of “The Dukes of Hazzard” or “Deliverance”.