With his performance in the 2015 PGA Championship at Whistling Straits, Jason Day set the 72-hole scoring record in relationship to par, becoming the first player to shoot 20-under total (268) in a men's major championship.
However, the 72-hole scoring record in the PGA Championship belongs to David Toms, who shot 15-under 265 when he won the 2001 PGA Championship at Atlanta Athletic Club. It's the second-best total in the history of major championships, only bettered by Henrik Stenson's winning 264 at the 2016 British Open Championship. Toms famously laid up on the final hole of the championship after a poor drive, managing to get up-and-down for a par to win his only major championship and hold off Phil Mickelson.
David Toms also owns the PGA Championship 54-hole scoring record with his 196 turned in at Atlanta Athletic Club in 2001. Ernie Els is second-best with a first 54 holes of 197 in the 1995 PGA Championship at Riviera Country Club.
The PGA Championship 36-hole scoring record is 130, set by Gary Woodland in 2018 at Bellerive Country Club with rounds of 64 and 66. He broke the prior record of 131, shared by an astounding nine players. Hal Sutton was the first to post 131 in the 1983 PGA Championship at Riviera Country Club, while Jimmy Walker and Robert Streb both posted 131 (11-under total) at the 2016 PGA Championship at Baltusrol.
The 18-hole scoring record at the PGA Championship is 63, with 14 total 18-hole rounds of 63 shot in the championship's history, starting with Bruce Crampton in 1975 at Firestone and most recently by Robert Streb in 2016 at Baltusrol in New Jersey.