Walker was in the lead after every round and finished at 14-under 266 just one shot ahead of defending champion and Australian Jason Day.

Had Day been successful, he would have joined Tiger Woods as the only golfers to successfully defend the PGA title since it went to stroke play in 1958.

Countryman Adam Scott finished at five-under with Aaron Baddeley securing a place in the top-50 at one-under.

Walker joins Danny Willett (Masters), Dustin Johnson (U.S. Open) and Henrik Stenson (British Open) as first-time major champions.

The last time that happened was 2011.

Daniel Summerhays was third at 10-under.