Dufner struggled to a 4-over 74 to lose to Johnson by one. The former Masters champion didn't have it easy in the final round either, as he closed with a 2- over 72 in what was a 2-man race throughout the final round.
For Johnson, it was his eighth PGA Tour victory and second at this event, adding to his triumph in 2010. He picked up another tour win last year at the John Deere.
Johnson has had a tough year with just two top-20 finishes in 10 PGA Tour starts. He also missed a pair of cuts and was a first-round loser at the WGC - Accenture Match Play Championship.
The field includes just eight of the top 30 in the world as several top players are competing in Europe this week. The last four winners have come from behind in the final round to earn the title.
Golf Channel has coverage the first two days and early on the weekend before handing off to CBS for Saturday's and Sunday's afternoon coverage.
The PGA Tour heads to Ohio next week for the Memorial Tournament, where world No. 1 Tiger Woods is scheduled to defend his title.
BMW PGA CHAMPIONSHIP, Wentworth Club, Surrey, England - Luke Donald carded his third 68 of the week in the final round last year to win the BMW PGA Championship for second straight year.
Donald, who returned to No. 1 in the world with the victory, joined Sir Nick Faldo and Colin Montgomerie as the only three players that have successfully defended their title at this event.
The Englishman beat Justin Rose and Paul Lawrie by four strokes. A year earlier, he fended off Lee Westwood in a playoff with the No. 1 spot in the world up for grabs.
Donald will be joined in the field at the tour's flagship event by 10 of his 2012 Ryder Cup teammates. Twenty of the 29 champions of this tournament have been Ryder Cup players.
Miguel Angel Jimenez, the 2008 champion, is playing just his second event of the year this week. He had missed a lengthy amount of time with a broken leg.
Golf Channel has extensive coverage of the action this week.
The European Tour heads to Sweden next week for the Nordea Masters, where Westwood cruised to a 5-shot win last year.
SENIOR PGA CHAMPIONSHIP, Bellerive Country Club, St. Louis, Missouri - European Tour veteran Roger Chapman fired a 7-under 64 in the third round last year, then hung on to win for the first time on the Champions Tour.
Chapman, who played his first major on the regular tour in 1977, had never come close to winning a major prior to this. He tied for 12th at the 1991 British Open, which stands as his best finish in a major on the regular tour.
From 2009-2011, Chapman played the Senior PGA Championship and the Senior British Open each year, but never finished better than tied for 27th. That came at the 2011 Senior PGA.
Last year's Senior PGA was Chapman's first Champions Tour start of the season. He later carded four rounds in the 60s to win the U.S. Senior Open for his second major championship on the senior circuit.
This year's host course, Bellerive Country Club, has hosted the U.S. Open, the PGA Championship, the U.S. Senior Open and two U.S. Mid-Amateur championships. The course will also host the 100th annual PGA Championship in 2018.
Golf Channel and NBC will broadcast the action this week.
The Champions Tour remains in Iowa next week with the Principal Charity Classic. Jay Haas rolled to a 5-stroke win last year over two players.
PURE SILK-BAHAMAS LPGA CLASSIC, Ocean Club Golf Course, Paradise Island, Bahamas - The LPGA Tour heads to the islands this week for a new event, the Pure Silk-Bahamas LPGA Classic.
This is the tour's first ever official appearance in the Bahamas. The field for the event will include nine of the top 10 and 15 of the top 20 players from the updated world rankings.
Every tournament winner from this season will be in the field as well.
Golf Channel has coverage all four days.
The LPGA Tour will remain near the beach next week as well as the tour heads to the ShopRite LPGA Classic, which will be played just outside Atlantic City, N.J. Stacy Lewis opened with back-to-back 65s before closing with a 71 to win by four.
MEXICO CHAMPIONSHIP, El Bosque Golf Club, Leon, Mexico - The Web.com Tour plays its final event outside the United States this week with the Mexico Championship.
Lee Williams led by one entering the final round last year, and carded a 2- under 70 to hang on for a 1-stroke win over Paul Haley.
Williams has moved on to the PGA Tour, where he has missed the cut in seven of his 13 starts. He also missed the cut in his one Web.com Tour start of the year. He will not defend his title this week.
The field includes 16 of the top 25 on the money list, and 14 players that have won on the PGA Tour.
The Web.com Tour travels to Maryland next week for the Mid-Atlantic Championship, where David Lingmerth rallied to victory last year.