Here, Press Association Sport takes a look at the man behind the golfer.
A 10-year-old Koepka sustained a broken nose and fractures to his sinus cavity when he was involved in a car accident, resulting in him being banned from playing contact sports for the summer. He took up golf as a suitable alternative, enrolled in a junior programme and that helped start him on his career path.
Golf's not his dream job
Despite his success Koepka is not a golf nerd and admits "golf is kind of boring". Given the choice he would have been a baseball player like his great uncle Dick Groat, a World Series winner with both the Pittsburgh Pirates and the St Louis Cardinals. He is also a fan of "proper football" and names Manchester United as his favourite team along with basketball franchise the Los Angeles Lakers.
Koepka's caddie Ricky Elliott is from Portrush, venue for this year's Open Championship. Elliott is a good golfer in his own right, winning titles such as the Ulster Boys Championship and the Ulster Youth Championship as well as representing Ireland at the 1990 European Youths Championship. Elliott previously worked for 2003 Open champion Ben Curtis, among others, before joining up with Koepka in 2013.
For most of his career Koepka was not known for expressing strong opinions, but the 29-year-old's success has made him more comfortable in saying what he thinks. "You're actually probably getting the real me now," Koepka said earlier this year. "I think before I was just trying to be politically correct and not stir any bubbles. I feel like now where I've put myself in the game, I've kind of established myself and I feel I actually do have a voice and it will be heard." Koepka has used that voice recently to claim "no-one ever has the balls" to penalise slow play and said Sergio Garcia "acted like a child" when he was disqualified for damaging greens in the Saudi International.
Koepka's girlfriend Jena Sims is a former Miss Georgia Teen pageant winner who moved into acting and has worked with the likes of Morgan Freeman, Robert De Niro and Michael Douglas in the film Last Vegas and also starred in movies such as Attack of the 50ft Cheerleader. Her work in television includes appearances in Entourage, Dexter, Vampire Diaries, CSI and One Tree Hill and she also runs the award-winning charity Pageant of Hope.