Langer got his fifth Champions Tour victory this season, and the second in the greater Seattle area after this year after winning the U.S. Senior Open at Sammamish, Wash., a month ago.
His 18-under-par total matched Loren Roberts' tournament record from last year.
Langer made consecutive birdies at Nos. 15 and 16 to stretch his lead to four strokes with just two to play at the TPC at Snoqualmie Ridge to take a four-shot lead over Price.
Price (71) wasn't able to find enough birdies on Sunday to keep up with the Charles Schwab Cup leader.
Hometown favorite Fred Couples closed with a 67 to finish in third at 9 under.