In February 2010, Fowler finished second at the Waste Management Phoenix Open with a score of 15-under-par at the TPC of Scottsdale course. In June, Fowler notched his third PGA Tour runner-up finish at the Memorial Tournament in Dublin, Ohio. Fowler entered the final round in the lead, but shot a 73 to finish behind Justin Rose, who recorded his first PGA Tour victory. This performance took Fowler into the top 50 of the Official World Golf Ranking.
Masters Tournament: Finished runner-up at the Masters, one stroke behind Patrick Reed, for his best result at the event. For the first time in eight starts at Augusta National, recorded four par-or-better rounds (70-72-65-67). Earned his third runner-up in a major (2nd/2018 Masters Tournament, T2/2014 The Open Championship, T2/2014 U.S. Open) and third top-five in the last four (2nd/2018 Masters Tournament, T5/2017 Open Championship, T5/2017 U.S. Open). With third-round 65, was one of just four players to post a bogey-free round during the week (Rory McIlroy/65, Jon Rahm/65, Si Woo Kim/65) with all four occurring in the final round.
World Golf Championships-Accenture Match Play Championship: In his fourth consecutive start at the World Golf Championships-Accenture Match Play Championship, fought his way to the semifinals Sunday morning against Ernie Els. Got off to a hot start, leading for seven of the first nine holes. With a shift of momentum, Els battled back and won three consecutive holes (Nos. 10-12) to gain a 2-up lead. Following an eagle and par on Nos. 13 and 14, he squared up the match. An Els birdie-3 at No. 18 sent the match to extra holes. A birdie-3 at the 19th hole (No. 1) gave him the upset win over Els.
Waste Management Phoenix Open: Won fifth PGA TOUR title at the Waste Management Phoenix Open in his 220th career start at the age of 30 years, 1 month, 21 days. Began the final round with a four-shot lead and won by two strokes after recording a double bogey and triple bogey en route to a closing 3-over 74. Became the first player since 1983 to win with both a double bogey and triple bogey or worse in the final round. Triple bogey came at No. 11 at TPC Scottsdale after he chipped his ball into the water and received an additional penalty when the ball rolled back into the water after he had placed it back into play. Marked the second time of seven occasions he converted a 54-hole lead to victory.
In the 2013–14 season, Lowry suffered a minor thigh strain in the club's pre-season friendly. Despite this, Lowry remained in the first team under the new management of Steve Lomas until he received a straight red card after a foul on Will Hughes, in a 5–1 loss against Derby County on 14 September 2013. After serving a three match ban, Lowry remained on the bench without playing for four matches Lowry made his first team return on 2 November 2013 when he came on as a substitute for Scott Malone against Burnley. However, his return, after spending two months without playing, was a disastrous when he scored an own goal, which saw Millwall drew 2–2. After this, Lowry was out of the first team, demoted to the substitute bench between mid-November and mid-December until he made his return on 26 December 2013, in a 4–0 loss against Watford. On 28 January 2014, Lowry was sent-off for the second time this season in the late-minutes against Sheffield Wednesday after fighting with Giles Coke, who also was sent-off as well, with both side drew 1–1. After serving a four match ban, Lowry was in the first team throughout February and March until he suffered a foot injury that kept him out for the remainder of the season. Lowry went on to finish the 2013–14 season, making twenty-two appearance.
BMW Championship: Entered the BMW Championship No. 36 in the FedExCup standings, with his T39 finish at Conway Farms outside Chicago leading to a final ranking of No. 38. Advanced to the TOUR Championship by Coca-Cola in 2012 (finished No. 28 in the FedExCup), but other three seasons led to near misses of cracking the top 30 in the FedExCup (No. 43 in 2011 and No. 32 in 2010).
Lowry missed the first three cuts of his professional career, but had his first payday on 5 July, when he finished 50th at the Open de France ALSTOM. He had his best professional result in November 2009, when he finished 3rd in the Dunlop Phoenix Tournament in Japan. In January 2010, Lowry finished in fourth place in the Abu Dhabi Golf Championship, moving him into the top-100 of the Official World Golf Ranking.
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.