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.
Fowler is one of four golfers in the "Golf Boys" group along with fellow PGA Tour players Ben Crane, Bubba Watson and Hunter Mahan. The Golf Boys released a YouTube video of the song "Oh Oh Oh" on the eve of the 2011 U.S. Open. Farmers Insurance is donating $1,000 for every 100,000 views of the video. The charitable proceeds will support both Farmers and Ben Crane charitable initiatives.
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."'
U.S. Open: Playing alongside eventual-champion Martin Kaymer in the final pairing Sunday, followed up his career-best round (3-under 67) in a U.S. Open with a final-round, 2-over 72 to remain T2 (the sixth runner-up finish of his career). It was his best performance in six U.S. Open starts (previous-best finish was a T10 in 2013). It was also his top major championship showing among his 18 starts (previous-best finishes were T5s at the 2011 Open Championship and the 2014 Masters). His pairing with the 29-year-old Kaymer was just the third final grouping at the U.S. Open since 1965 with two players in their 20s. The others were John Mahaffey (28) and Jerry Pate (22) in 1976 and Woods (26) and Sergio Garcia (22) in 2002.
BMW Championship: After entering the final round of the BMW Championship in a second-place tie with Jason Day (five strokes behind Marc Leishman), recorded a 4-under 67 to finish T2, his 11th career runner-up on the PGA TOUR. Week was highlighted by a career-best, six consecutive birdies in the first round on Nos. 12-17. Chipped in from 64 feet on the 17th.
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.