Six weeks after winning the Masters, Johnson won the 2007 AT&T Classic in a playoff over Ryuji Imada. Following the win, Johnson moved to a career-best 13th in the world rankings. His next PGA TOUR victory, and first outside the state of Georgia, came at the 2008 Valero Texas Open. Johnson won the Sony Open in Hawaii in January 2009, and successfully defended his title at the Valero Texas Open in May with a playoff victory over James Driscoll. With a third-round 60, Johnson became the first player to shoot 60 twice on the PGA TOUR, having done so previously at the 2007 Tour Championship. The win was Johnson's sixth on tour. Other highlights in 2009 include a tie for 2nd place at the John Deere Classic and a solo 3rd place finish at the Arnold Palmer Invitational. He finished the season ranked a career best fourth on the money list.
His 2010 season on the PGA TOUR got off to a slow start, but his luck turned with a victory at the 2010 Crowne Plaza Invitational at Colonial, his seventh PGA Tour win. In 2011, Zach had four top 10 finishes, with his highest being a tie for third at the John Deere Classic. In 2012, he finished second at both THE PLAYERS Championship and the RBC Heritage tournament and won both the Crowne Plaza Invitational at Colonial and the John Deere Classic, giving him a total of nine career wins on the PGA TOUR. Zach also qualified for the 2012 Ryder Cup team, which was played at Medinah Country Club in September.
On July 20, 2015, Johnson beat Louis Oosthuizen and Marc Leishman in a 4-hole playoff to win the Open Championship at St Andrews for his 12th PGA Tour win and second major. He became only the sixth golfer to win majors at Augusta and St. Andrews, the others being Sam Snead, Jack Nicklaus, Nick Faldo, Seve Ballesteros, and Woods.
Zach and Kim have three children, Will, Wyatt and Abby Jane (AJ) and reside in St. Simons Island, Georgia.