Couples fired a 3-under 67 in the final round, good for a two-shot victory in the second major tournament on the U.S. senior circuit calendar.
The victory was the eighth of Couples' senior career. He finished at 9-under-par 271, besting Gary Hallberg, who ended with a 4-under 66 for sole possession of second place at minus-7.
Sharing third place were Carl Mason (66), Dick Mast (67) and Barry Lane (69) at 4-under 276.
Tumbling from a share of third-round lead into sixth place was 2010 champion Bernhard Langer, who fell to a 5-over 75.