Lowry made his professional debut in the 2009–10 UEFA Europa League in an away fixture at Rapid Vienna. On 17 September 2009, Lowry signed a three-month loan deal with Football League Championship side Plymouth Argyle. Lowry made his Plymouth Argyle debut on 19 September 2009, playing 90 minutes, in a 3–1 loss against Newcastle United. He played 13 league games for Plymouth during his loan spell, where he impressed many and was recalled by Villa who required Lowry's services as cover after some injuries to defenders.
After a tie for fifth at the Masters in April, Fowler had his best finish of 2014 at the U.S. Open at Pinehurst No. 2 in North Carolina. Fowler was runner-up with Erik Compton at −1, best finishes for both at a major, but they were eight strokes behind champion Martin Kaymer. Fowler had another second-place finish, at the Open Championship at Royal Liverpool Golf Club in Hoylake, England. He began the final round six strokes behind Rory McIlroy and finished the day tied for second with Sergio García at −15, two strokes behind McIlroy. At the next major in August, the PGA Championship, Fowler, Phil Mickelson, Henrik Stenson, and McIlroy battled for the title on a rain-soaked Valhalla Golf Club, near Louisville. Despite holding the lead for a good portion of the day, Fowler tied for third. He was only the third player, along with Jack Nicklaus and Tiger Woods, to have finished in the top 5 in all four majors in one calendar year, but the first not to win (Jordan Spieth became the fourth player in 2015). Fowler had 10 top-10 finishes during the 2013–14 season. His 8th-place finish at The Tour Championship moved him to 10th in the world golf rankings.
DeChambeau made his PGA Tour debut as an amateur in June 2015 at the FedEx St. Jude Classic near Memphis, Tennessee, and finished in 45th place. He played in his first major championship at the U.S. Open at Chambers Bay, but missed the cut by four strokes. DeChambeau was unable to defend his NCAA title in 2016 after the SMU athletic department was handed a postseason ban by the NCAA. He decided to forgo his senior season to play in a number of events before turning professional. At the 2015 Australian Masters in November, DeChambeau was runner-up with John Senden and Andrew Evans, two shots behind the winner Peter Senior. He was the low amateur at the Masters in 2016 and tied for 21st place.
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).
At the PGA Championship, Fowler carded 74-69-75-68 to finish with a six-over par total of 286, in a tie for 51st place. Early on the third day Fowler rocketed up the leaderboard with three birdies in the first five holes only to falter later in the round with two triple bogeys, effectively ending his hopes of a first major championship and PGA Tour win.
Nationwide Tour Players Cup: Playoff runner-up to Derek Lamely at the Nationwide Children's Hospital Invitational. Started the final round five shots behind 54-hole leader Dave Schultz. Held the lead during much of the final round but suffered a bogey at the 72nd hole of regulation to drop into a tie with Lamely and force a playoff. Lost to Lamely when he failed to get up and down from a greenside bunker on the second extra hole, missing his par putt of 12 feet. Lamely rolled in a three-foot par putt to win.
2019 Open Champion Shane Lowry, compared to Tommy Fleetwood, is on the other side of the spectrum in regards to brand loyalty. He is Cleveland/Srixon in 12 clubs including the ball with the only two exceptions being the TaylorMade M4 3-wood and his Odyssey Putter. In this case, that makes sense, those clubs seem to be a challenge to swap, especially the 3-wood, and Cleveland/Srixon isn’t really known for putters on the PGA Tour.
In September, he signed a clothing deal with Puma. In the same month, he was also chosen as a captain's pick for the U.S. Ryder Cup team. At age 21 years and 9 months when the matches began, Fowler became the youngest U.S. Ryder Cup player of all time, and only European Sergio García was younger when he made his Ryder Cup debut in 1999. Fowler forfeited a hole during foursomes competition on the first match day because of a rules violation, by taking a permissible free drop from muddy conditions in an improper location, a mistake U.S. captain Corey Pavin attributed to Fowler's inexperience. On the final day of the competition in his singles match against Edoardo Molinari, Fowler birdied the last 4 holes to halve the match after having been 4 down after 12 holes.
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).
Lowry elected to turn professional the week after his Irish Open triumph, meaning that he would miss out on the opportunity to play in the Walker Cup in September 2009. He made his professional début on 28 May at the European Open, where he shot 78 in the first round to end the opening day almost at the back of the field, and went on to miss the cut following a second round 73.