Day finished the tournament at 15 under, four shots ahead of Kevin Chappell.
According to ESPN Stats & Info, he's the first golfer to go wire to wire twice in one season since Tiger Woods in 2002.
The 28-year-old got off to a blistering start at The Players Championship. His opening-round 63 tied a course record, per Doug Ferguson of the Associated Press. He then carded a 66 in the second round. Those scores put Day in the driver's seat, and he merely needed to avoid any costly mistakes in the final two rounds in order to secure the title.