The U.S. captain won the title on floor exercise Tuesday, about an hour after getting a bronze on balance beam. Add in her gold with the Fierce Five, and she leaves London with three medals, most of any of the Americans.
It's the first Olympic gold on floor exercise for a U.S. woman.
Catalina Ponor of Romania won the silver, and Aliya Mustafina of Russia got the bronze.
World champion Jordyn Wieber was seventh. The pre-Olympic favourite failed to win any individual medals.