Lowry made his debut for the Glory on 30 January 2016, starting against Melbourne Victory. Lowry then scored his first Perth Glory goal on 20 February 2016 when he scored a header in the 41st minutes, to give Brisbane Roar a thrashing with a 6–3 win for Perth Glory. Throughout the 2015–16 season, Lowry established himself in the starting eleven and formed a central defense partnership with Alex Grant, as he made ten appearance for Perth Glory in his first half of the season.
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.
Lowry was the 2007 Irish Amateur Close Champion, defeating Niall Turner 4 & 3 in the final. While still an amateur in May 2009, he won The Irish Open on the European Tour, defeating Robert Rock on the third hole of a sudden death playoff. The win, on his tour début, made him just the third amateur to win on the European Tour, following Danny Lee earlier in the 2009 season, and Pablo Martín in 2007. Lowry shot a 62 to equal the lowest ever by an amateur on the circuit and led from the second round onwards.
“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.
After Lowry's loan spell at Leeds was coming to an end, on 11 May he signed a new two-year contract extension at Aston Villa. It was a remarkable few days for Lowry, he was promoted with Leeds, received a call up to Australia's World Cup Squad and on the same day he signed a new two-year deal with Villa. Despite signing a contract with the club, Leeds United was considering re-signing him for the second time ahead of the 2010–11 season, but never happened.
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.
In May 2012, Fowler won the Wells Fargo Championship in Charlotte on the first extra hole of a sudden-death playoff. Replaying the 18th hole, he defeated Rory McIlroy and D. A. Points with a birdie to gain his first PGA Tour win. Fowler shot a 69 (−3) in the final round to finish in a three-way tie after 72 holes at Quail Hollow Club. This win enabled Fowler to break the top-25 in the world, placing him at number 24. The following week at The Players Championship in Ponte Vedra Beach, Florida, Fowler played the final hole at −11 under par and had a birdie opportunity to bring him within one of leader and eventual winner Matt Kuchar. Fowler, however, pushed his putt to the right and finished in a tie for second, the fifth second-place finish of his career.
On August 26, 2018, he won The Northern Trust for his first playoff victory; in the process, he established a new record for the tournament when held at the Ridgewood Country Club, with a score of 266, besting the old Ridgewood record of 270, which was set in 2014 by Hunter Mahan. The following week, he won at the Dell Technologies Championship played at TPC Boston in Norton, Massachusetts, with a final score of −16, two shots clear of Justin Rose. This put him over 2000 points ahead of the second place player, Dustin Johnson, in the FedEx Cup rankings. This margin secured him top seeding at The Tour Championship, regardless of his finish at the BMW Championship. This also marked his fourth win on tour, third for the year, and second during the playoffs. At the Tour Championship, DeChambeau finished 19th out of 30 participants. As a result, he fell to 3rd in the FedEx Cup, winning $2,000,000.
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.
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).
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).
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).