Johnson shot 4-under 66 on Sunday at TPC Southwind to win the FedEx St. Jude Classic by a shot over John Merrick at 9 under par. The win is Johnson's sixth on the PGA Tour, as he has earned a victory in each of his first five years on Tour.
The 27-year-old broke out of a logjam among the leaders in Memphis with two birdies in the final three holes. With just one threesome behind Johnson on Sunday, the final three players on the course were unable to match him and force a playoff.
In the group ahead of Johnson, world No. 2 Rory McIlroy had a chance to tie at the 18th hole, but the Ulsterman hit his tee shot at the par-4 finishing hole into a water hazard. Instead, McIlroy made a double-bogey 6 to card 1-under 69 and finish three shots behind Johnson in a tie for seventh with Robert Allenby, Seung-Yul Noh and Ken Duke.