In the 2012–13 season, Lowry regained his first team place, playing in the left-back and central defense positions until he missed one game after picking up a yellow card for the fifth time against Bristol City on 2 October 2012. After making his first team return as a left-back, Lowry then provided assist for the winning goal when he set up a goal for Chris Woods, in a 1–0 win against his former club, Leeds United on 18 November 2012. Lowry was then banned for two matches between 19 January 2013 and 25 January 2013 after picking up a yellow card for the tenth time this season. Lowry then He "curled a superb, dipping free-kick" to score from 35 yards (32 m) as Millwall beat Charlton Athletic 2–0 at The Valley on 16 March 2013. Lowry played in all matches in the run up to the Lions' FA Cup semi final against Wigan Athletic at Wembley, though he missed one match in the 4th round against his former club, Aston Villa. In late-April, Lowry was given a three match ban after being booked for the fifteenth time this season. Despite this, Lowry finished the 2012–13 season, making forty-five appearance and scoring once in all competitions.
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."'
Quicken Loans National: Starting the final round of the Quicken Loans National seven shots back, the Quicken Loans ambassador recorded a career-best nine birdies to post his low round of the week, a 5-under 65 to finish T3. Marked his third top-five in his last four starts. Chances for victory took a serious hit with a double bogey (the only one of the final round) on No. 14, the easiest hole in the final round. Marked second top-three finish in six starts at the Quicken Loans National (2015-2nd).
Immediately after the Masters in mid-April 2016, DeChambeau turned professional and signed a long-term agreement with Cobra-Puma Golf. He made his pro debut days later at the RBC Heritage in South Carolina and tied for fourth, earning over $259,000. The decision to turn professional meant the forfeiture of his exemptions to the U.S. Open at Oakmont and Open Championship at Royal Troon; he qualified his way into the U.S. Open, tied for fifteenth place for over $152,000, and improved his world ranking to 148.
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.
Wells Fargo Championship: Made birdie-3 on the first extra hole (No. 18) to defeat Rory McIlroy and D.A. Points at the Wells Fargo Championship for his first TOUR win. Improved to 1-1 in playoffs (lost to Troy Matteson, 2009 Frys.com Open). The playoff was the fifth at the Wells Fargo Championship. At the age of 23 years, 4 months, 23 days, became the third player to make the Wells Fargo Championship his first PGA TOUR win (Anthony Kim in 2008 and McIlroy in 2010). Became the third-youngest winner of the event, behind McIlroy (20 years, 11 months, 28 days) and Kim (22, 10, 15). His win came in his 72nd start on TOUR and was his 16th top-10 finish. Opening-round 66 is the lowest start by a winner of the Wells Fargo Championship. Won in his third start at the Wells Fargo Championship (T6 in 2010 and T16 in 2011).
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.
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.
A better look at my @cobragolf proto irons…second and third pics are top down view of 8 (40°) and 4 (24°) iron…we started working on these back in January…I wanted an old school look (thin/straight top line and no offset) while keeping the benefits of the sole and weight behind the sweet spot (tungsten plugs) these are all hand milled stainless heads…currently working on a pvd finish for the final version…stay tuned👌