Presidents Cup: Closed out his second consecutive Presidents Cup appearance with a 6-and-4 victory over Emiliano Grillo, helping lead the United States to a 19-11 win over the International Team. Compiled a 3-0-1 overall record, highlighted by victories the first two days with teammate Justin Thomas in Foursomes (6 and 4 over Charl Schwartzel and Hideki Matsuyama) and Four-ball (3 and 2 over Branden Grace and Louis Oosthuizen).
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).
In 2008, Fowler repeated as Sunnehanna Amateur champion. In the first round of the U.S. Open, Fowler shot a −1 (70) and was in a tie for 7th place. He was one of three amateurs to make the cut, along with Derek Fathauer and Michael Thompson. He ended the tournament tied for 60th. In October 2008 Fowler played on the Eisenhower Trophy team that finished second. He was the leading individual player.
Quicken Loans National: Starting the final round of the Quicken Loans National seven shots back, the Quicken Loans ambassador recorded a career-best nine birdies to post his low round of the week, a 5-under 65 to finish T3. Marked his third top-five in his last four starts. Chances for victory took a serious hit with a double bogey (the only one of the final round) on No. 14, the easiest hole in the final round. Marked second top-three finish in six starts at the Quicken Loans National (2015-2nd).
After Lowry's loan spell at Leeds was coming to an end, on 11 May he signed a new two-year contract extension at Aston Villa. It was a remarkable few days for Lowry, he was promoted with Leeds, received a call up to Australia's World Cup Squad and on the same day he signed a new two-year deal with Villa. Despite signing a contract with the club, Leeds United was considering re-signing him for the second time ahead of the 2010–11 season, but never happened.
The Barclays: Held a one-stroke lead over Patrick Reed after 54 holes at The Barclays in the FedExCup Playoffs, before a double bogey-birdie-bogey finish on Nos. 16-18 resulted in a T7 at 6-under 278 with Jason Kokrak and Ryan Moore. Fowler went bogey free at Bethpage Black from the 10th hole in round one until the 11th hole in the final round, a span of 55 holes. His 55-consecutive holes without a bogey became a personal best on the PGA TOUR, besting 53 from the 2010 Memorial Tournament. This streak also marked the longest recorded in Barclays history since hole information began in 1983. Ian Poulter had the longest with 45 in 2010. The finish marked his third top-10 showing in his last four starts in the event (T9/2013, T9/2014).