BMW Championship: At No. 22 in the FedExCup standings heading into the third Playoffs event, the BMW Championship, he bogeyed No. 17 in a final-round even-par 72 to miss advancing to the TOUR Championship by half a point, finishing the season No. 31 in the FedExCup standings. Charl Schwartzel fired a final-round 8-under 64 to claim the No. 30 position.
In June 2015, he became the first SMU Mustang to win the NCAA individual championship, recording a score of 280 (−8) to win by one stroke. In August, he won the U.S. Amateur title, defeating Derek Bard 7 & 6 in the 36-hole final. He became the fifth player to win both the NCAA and U.S. Amateur titles in the same year, joining Jack Nicklaus (1961), Phil Mickelson (1990), Tiger Woods (1996), and Ryan Moore (2004).
At the first FedEx Cup playoff event of the season, The Barclays, Fowler went into the final round leading the event by one stroke. He endured a difficult final round, shooting a two-over-par 74. His challenge was ended with a double-bogey at the 16th hole that put him four strokes behind playing partner Patrick Reed. He went on to finish T7, three strokes behind the winner Reed. As a result of this, Fowler also failed to secure his automatic Ryder Cup spot, which he would have done with a top-three finish. Fowler moved up from 28th to 16th in the FedEx Cup standings with this result.
Aberdeen Asset Management Scottish Open: Earned his second international victory when he captured the Aberdeen Asset management Scottish Open in come-from-behind fashion at Gullane GC in July. After a bogey on the 14th hole Sunday, fell two shots off the lead. He responded with three birdies over his final four holes to catch and pass American Matt Kuchar, who shot a final-round 68 to post the clubhouse lead at 11-under. He made a 9-foot birdie putt at No. 15, made a two-putt birdie at the par-5 16th, parred the 17th then hit his approach shot on the par-4 finishing hole to 2 feet for the tap-in birdie and the title. Joined seven other players who made the Scottish Open their first European Tour win.
Born in Modesto, California, to John Howard Aldrich DeChambeau and Janet Louise Druffel, DeChambeau moved to Clovis, east of Fresno, at age seven. He attended Clovis East High School and won the California State Junior Championship at age 16 in 2010. DeChambeau graduated in 2012 and accepted a scholarship to Southern Methodist University in Dallas, Texas, majoring in physics.