Simpson saved par on the hilly 18th hole with a chip from the rough to about 4 feet, closing with a 2-under 68 to hold off Graeme McDowell and Michael Thompson in a foggy final round at The Olympic Club on Sunday. Simpson finished at 1-over 281.
Michael Thompson and Graeme McDowell were a shot back.
McDowell missed a birdie putt from about 25 feet on the final hole that would have forced an 18-hole playoff Monday. The Northern Irishman won the title at Pebble Beach two years ago.
Tiger Woods closed at 7 over after 73.