The two started working together in 2013 when Koepka was playing on the European Challenge Tour. Harmon was by Koepka's side for all four of his major championship victories, and his rise to No. 1 in the world.
“I was informed on the Wednesday after the Masters that he wanted to go in a different direction,” Harmon said.
Coincidentally, Harmon is also Dustin Johnson's swing coach, and he won the green jacket in November.
“I love Claude, we had a great run and he’s still family to me, but unfortunately we’re not working together anymore,” Koepka told Golfweek via text.
Koepka went winless in 2020 for the first time in his career while battling injuries for much of the season. He now sits No. 12 in the world ranking.