The Open Championship: Finished T6 at the 147 Open Championship at Carnoustie, his first top-10 in a major since at T6 at the 2013 Open Championship. Week was highlighted by a third-round 66, his lowest round in a major since a 66 in the second round of the 2011 Masters. Was just his second made cut (2018 Masters Tournament/T32) in his last six major starts. Posted rounds of 71-71-66-71, the first time since the 2010 Masters Tournament (T4) he recorded four par-or-better rounds in a major. Paired with eventual-champion Francesco Molinari, entered the final round four shots off the lead. Took the solo-lead at 7-under after nine holes, one ahead of Molinari and Jordan Spieth, but his lead disappeared with a double bogey at No. 11. Bogeyed No. 12 and birdied No. 14 before closing with four pars to finish at 5-under. The finish moved him to No. 50 in the Official World Golf Ranking, returning to the top 50 for the first time since January 2015. The ranking also earned him a spot in the World Golf Championships-Bridgestone Invitational.
Hero World Challenge: Hero World Challenge host finished T9 and 10 strokes behind champion Rickie Fowler. Marked his first appearance in competition since withdrawing from the Omega Dubai Desert Classic on February 2, 2017. Week included playing in the first and final round with reigning FedExCup champion and PGA TOUR Player of the Year Justin Thomas, with both players posting scores of 69-68 in those rounds.
Won seven times en route to capturing the inaugural FedExCup, cruising through the PGA TOUR Playoffs for the FedExCup with two wins and a T2 in three starts. Captured 13th career major championship (second all-time to Jack Nicklaus' 18) and finished the year with 61 official PGA TOUR victories, fifth all-time. Adjusted scoring average was 67.79, matching own record set in 2000. With 60 official rounds, won his seventh career Vardon Trophy and also captured the Byron Nelson Award.