Here are the key stats from the final round at Baltusrol, where Walker emerged with the Wannamaker trophy:
• Walker won his first career major championship in his 18th start, making it four different first-time major champs this season. This is just the fifth year with four different major winners in the same season, with the last coming in 2011.
• Walker, who is projected to move into the top 15 in the Official World Golf Ranking with the win, is the oldest first-time major winner from the U.S. since Todd Hamilton in 2004, and is the lowest-ranked major winner (48th) since Keegan Bradley in 2011 (108th).
• Walker went 0-for-187 on the PGA Tour to begin his career. He has six wins and more than $13 million in earnings since.
• Walker closed out the victory by making a par putt on 18 from 2 feet 11 inches away. It capped a 37-for-37 week of putts inside 3 feet.
• Day finished runner-up for the fourth time in his major career (all since beginning of 2011). He has the second-most runner-ups in that span behind only Mickelson.
• Henrik Stenson, who was trying to become the second player over 40 to win consecutive majors, finised in the top 10 for the 11th time in his career (all since 2008).
• Walker's win means Jordan Spieth went majorless in 2016 after winning two majors last year. The last player to win a major after a multi-major season was Woods in 2006.
Note: Golf Channel’s editorial research unit contributed to this report.