Lowry made his Leyton Orient debut, playing as a left-back position, in the opening game of the season, which saw Leyton Orient lost 2–1 to Chesterfield. Since his debut, Lowry established himself in the left-back position in the first half of the season despite being sidelined with suspension and fitness concern that saw him out for two matches. Following his return to the first team, Lowry played in the central-defense between December and March until he dropped from the first team throughout March. Lowry went on to make his first team return throughout 2014–15 season, making thirty-four appearance in his first season at Leyton Orient.
Frys.com Open: At the Frys.com Open in Scottsdale, Ariz., reached a three-way playoff with Jamie Lovemark and eventual-winner Troy Matteson. Began the final round four strokes behind Matteson, but played his first five holes in 5-under, punctuated by a hole-in-one from 211 yards at the par-3 fifth hole. After finishing T2 in the playoff, he had recorded all eight of his professional rounds in the 60s. Thanks to the T7 in Las Vegas at the Justin Timberlake Shriners Hospitals for Children Open and T2 finish at Grayhawk GC, he surpassed No. 150 from the 2008 money list, earning special temporary membership on TOUR for the remainder of the season.
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.
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).
Lowry did not win on the European Tour from 2016 to 2018 but was joint runner-up in the 2017 DP World Tour Championship, Dubai and runner-up in the 2018 Andalucía Valderrama Masters. In January 2019 he won the Abu Dhabi HSBC Championship by a stroke from Richard Sterne. Lowry led by 3 strokes after three rounds but was two-over-par after 11 holes of his final round and dropped 4 shots behind Sterne. However he finished with 3 birdies in the final 7 holes, while Sterne had two bogeys, giving Lowry the victory.
Fowler has three tattoos. One is a block "G" near his left elbow in honor of Georgia Veach, the daughter of a Seattle pastor and friend. Georgia was diagnosed with lissencephaly. Fowler got the tattoo just before the 2015 Presidents Cup. The second is from January 2016 and contains the name Yutaka Tanaka (Rickie's grandfather) in Japanese script on his left biceps. The third tattoo came just weeks after playing at the 2016 Summer Olympics and is of the Olympic symbols.
Lowry won for the first time as a professional in 2012, at the Portugal Masters in October. He shot a 67 to tie for the lead with the Englishman Ross Fisher, who made bogey on the final hole after missing a four-foot putt. The victory lifted Lowry back into the Official World Golf Ranking top 100 and made him eligible to compete in the WGC-HSBC Champions.
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.