The Federal Aviation Administration on Sunday said the jet was flying Saturday night from Philadelphia to Dallas, where Bush lives, and was diverted to Louisville, Ky. No one was hurt.
Bush spokesman Freddy Ford was on board and said the plane continued to Dallas after a brief stop. He said he never saw or smelled smoke.
FAA spokeswoman Holly Baker said the Gulfstream 4 declared an emergency due to the "smell of smoke in the cockpit" and landed without incident. She didn't elaborate.
Bush is honorary chairman of The First Tee, which supports youth education programs through golf, and had attended a Philadelphia event.