On 23 November 2011, Lowry was again loaned out to play in the Championship, this time to Millwall until 3 January 2012. He followed Aston Villa team-mate Nathan Baker who also signed on loan for Millwall two days earlier. Lowry made his Millwall debut three days later, where he played 90 minutes, in a 0–0 draw against Crystal Palace. His impressive display at Millwall soon earned a loan extension. Weeks later on 13 January 2012, Lowry was sent-off in the 22nd minutes after stamping on Nikola Žigić, which saw Millwall lose 6–0. Three years on after signing for Birmingham City, Lowry stated, quoting: "Whatever club I play for I fully commit to that club at the time. I play with my heart on my sleeve. Sometimes in the past I have gone overboard but I was a younger player then, I have learned a lot from these types of experiences. But I am an aggressive player, that’s the way I like to play and I can’t change the way I play. I will use my experience now and be a bit more clever."'
THE PLAYERS Championship: A week after collecting his first PGA TOUR victory, nearly became the first player since David Duval (1997) to post first two TOUR victories in back-to-back weeks, finishing T2 at THE PLAYERS, two strokes behind winner Matt Kuchar. Holed a birdie attempt from 21 feet, 7 inches on the par 3 17th in the final round to move to 11-under but couldn't convert a 7-foot, 7-inch birdie on No. 18 that would have given him the clubhouse lead at 12-under. Recorded his fifth career runner-up finish on TOUR in his 73rd start. His T2 performance came in his third start at THE PLAYERS and first in which he made the 36-hole cut. Moved into contention with a 66 in the third round, a career low at TPC Sawgrass. Entered the final round three shots off the 54-hole pace.
BMW Championship: At No. 22 in the FedExCup standings heading into the third Playoffs event, the BMW Championship, he bogeyed No. 17 in a final-round even-par 72 to miss advancing to the TOUR Championship by half a point, finishing the season No. 31 in the FedExCup standings. Charl Schwartzel fired a final-round 8-under 64 to claim the No. 30 position.
“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 switch was very easy. Even though he had won early in the year with another driver, he was not driving it good at all. He is very loyal to our team and our products that he came to us to find a new driver. He instantly loved the look of the Z 585 and once we started testing the numbers were exactly what he was looking for. His main comment about the driver is how his misses are minimal and he can hit all the shots he wants to.”
Waste Management Phoenix Open: Two weeks after the win in Abu Dhabi, made his eighth consecutive start in the Waste Management Phoenix Open, where he found himself three strokes off the lead after 54 holes. A final-round 4-under 67, capped off by a clutch birdie on the 72nd hole, forced sudden death with Hideki Matsuyama. On the fourth extra hole, the par-4 17th, an errant tee shot found the water hazard for the second time of the day. Matsuyama made par to win. Ranked second in Strokes Gained: Tee To Green and T1 in Strokes Gained: Total at TPC Scottsdale.
Deutsche Bank Championship: Shot a final-round 3-under 68 to come from one shot back and defeat third-round leader Henrik Stenson at the Deutsche Bank Championship, good for his third career PGA TOUR victory. Earned the win at age 26 years, 8 months, 25 days in his 150th career start. Collected 2,000 points and moved from No. 22 to No. 3 in the FedExCup standings. Has come from behind to win all three of his PGA TOUR events, with his first two wins via playoffs (2012 Wells Fargo Championship and 2015 PLAYERS Championship). Became the sixth consecutive come-from-behind winner at TPC Boston.
Lowry received his first call-up to the full Australia squad for a friendly against the Netherlands in Sydney and the Asian Cup qualifier against Oman in Melbourne in October. He did not play in either match. On 11 May 2010 he was selected as part of Pim Verbeek's 30-man provisional squad for the 2010 World Cup, and travelled to South Africa, but was not included in the final 23-man World Cup squad. Lowry was named in Han Berger's 18-man squad for an August 2010 friendly against Slovenia, but he did not appear in the match.
The Open Championship: Playing in the final group Sunday for the second straight time in a major championship, made a solid bid for the title, at The Open Championship, with a final-round, 5-under 67. Along with Garcia, finished second to Rory McIlroy by two strokes. With his finish at Royal Liverpool GC, became the only player of the season to claim top-five finishes in the year's first three major championships. He also became the first player to claim top-10 finishes in a season's first three majors since Woods achieved the feat in 2005. His T2 at Royal Liverpool supplanted his previous-best Open Championship finish (in four starts) of T5 in 2011. Rounds of 69-69-68-67 made him the only player in the field to post all four rounds in the 60s.
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.
Hyundai Tournament of Champions: Finished T6 in a Monday-start-Tuesday-finish event, the season-opening, 54-hole Hyundai Tournament of Champions. The event "started" twice during the regularly scheduled first round Friday and later Sunday, but both times PGA TOUR rules staff halted play due to unplayable windy conditions and subsequently voided all scores that had taken place. As the first player off the tee, he ended up hitting three "opening" shots of the season.