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.
The Open Championship: Enjoyed his best finish among seven major championship starts, with a T5 at The Open Championship at Royal St. George's. Opened with three par-or-better rounds to enter the final round three strokes behind Darren Clarke. Closed with a 2-over 72 in windy conditions to finish tied with fellow Americans Chad Campbell and Anthony Kim.
Though he appeared in two matches as an un-used substitute for Aston Villa in the 2010–11 season, Lowry continued to be remain out of the first team and in January 2011, Lowry signed for Championship side Sheffield United until the end of the season making his first start for the Blades away at Coventry City a day later. Lowry made eighteen appearances for the Blades but with the club in decline he was unable to prevent them from being relegated at the end of the season.
In July 2011, Fowler tied the 54-hole lead at the AT&T National, but an early double bogey on Sunday derailed his opportunity for his first PGA Tour win. Two weeks later Fowler finished tied for 5th in The Open Championship at Royal St George's. In August, Fowler finished in a tie for second at the WGC-Bridgestone Invitational behind winner Adam Scott, lifting him to 28 in the world rankings.
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.
While serving a suspension, Lowry signed a two-and-a-half-year permanent deal to Millwall for an undisclosed fee on 27 January 2012. Lowry then made his first appearance for the club since joining Millwall permanently, playing 90 minutes, in a 2–1 loss against rivals' West Ham United on 4 February 2012. Right way through March, Lowry was sidelined with ankle injury that kept him out for weeks. After making his first team return against Cardiff City, in a 0–0 draw on 31 March 2012, Lowry scored his first Millwall goal, which he scored the only goal in the game, in a 1–0 win over Coventry City on 17 March 2012. Lowry finished his 2011–12 season, making twenty-two appearance and scoring once.
Hero World Challenge: After beginning the final round seven strokes out of the lead, closed with a tournament-record, personal-best 11-under 61 to win the Hero World Challenge by four strokes over Charley Hoffman. With a winning score of 18-under 270, won at the age of 28 years, 11 months and 20 days. His 61 topped the previous Hero World Challenge course record of 62, set by Albany resident Justin Rose during the final round in 2015. Prior to his 61, the previous low final-round score by a Hero World Challenge winner was 64, set on three occasions and most recently by Luke Donald in 2005. Opened his final round with seven birdies before making his first par on the par-4 eighth hole. No player has had as long a streak of birdies in an official PGA TOUR event to open a round since Joe Durant started round four of the 2005 Honda Classic with seven in a row. Added a birdie on the ninth hole to make the turn with an 8-under 28, turning a seven-stroke deficit into a two-stroke lead. His final round included 11 birdies, two more than his benchmark of nine birdies in official PGA TOUR events (final round of the Quicken Loans National in 2017). Finished the week at Albany Golf Club with 30 birdies, three more than his highest total in official PGA TOUR events (27 – 2017 Houston Open). Recorded his sixth top-six finish at the event in his sixth start (1/2017, T3/2016, 3/2015, T6/2014, T4/2012, T6/2011).
“I was literally thinking I’d need surgery but I talked to Greg, he was like no, no, no, don’t do any of that, we’re going to teach your body to tolerate the force. Usually when ligaments get torn or bones get broken or whatever it’s because the muscles aren’t functioning properly, so thats what I’ve been doing.” He’s been focusing on exercises that get him into “extreme positions of rotations and flexions” at which point he adds weight to build mental and physical tolerance in those positions.
The Honda Classic: After beginning the final round of The Honda Classic with a four-stroke lead, posted a 1-over 71 to win by the same margin for his fourth career PGA TOUR title. It marked the first of five 54-hole leads he converted to victory. Opened with back-to-back 66s for the second consecutive year and posted a 65 in the third round to post the best 54-hole total since the event moved to PGA National in 2007 at 13-under 197. Seized the 54-hole lead with the widest margin of his career entering a final round. Turned in 2-over 37, but posted three birdies on the back nine to take command of the tournament. Despite bogeys on the 71st and 72nd holes, claimed his first victory since the 2015 Dell Technologies Championship. Finished the week second in Strokes Gained: Putting (7.392) and moved to 10th in the FedExCup standings and ninth in the Official World Golf Ranking, his first time in the top 10 since the 2016 BMW Championship.
PGA Championship: Finished T3 and two strokes behind McIlroy at the PGA Championship in his 20th major championship start, with T19 in 2013 the previous-best finish in four prior PGA Championship starts. Became the first to claim top-five finishes in all four majors since Woods in 2005. Since 1934, is just the third player to perform the feat, joining Woods in 2000 and 2005 and Jack Nicklaus in 1971 and 1973. Played all four majors in 32-under, with McIlroy second on the list, at 27-under.
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 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.