Kammala jumla mai zuwa: Koepka ya yi ikirarin babban zakara na farko a gasar US Open a 2017 a Erin Hills, Wisconsin. Ya samu nasarar kare mukaminsa a
2018 a Shinnecock Hills a Long Island, golfer na farko da ya lashe gasar US Open a jere tun lokacin da Curtis Strange a 1988 da 1989. Ya lashe babbansa na uku a Gasar PGA ta 2018 a Bellerive Country Club, yana harbi babban zakara-rikodin-daidaita 264 a kan ramuka 72. Nasarorin da ya samu a 2018 a US Open da PGA Championship su ne na farko da aka samu na wannan sau biyu tun lokacin da Tiger Woods a 2000. Ya lashe babbansa na hudu a Gasar PGA ta 2019 a Bethpage Black.