Made his major debut at The Open in 2018 and started in style with a 67 at Carnoustie that put him joint second en route to an eventual tie for 17th.
Van Rooyen represented South Africa in the World Cup later that year, while on his next major start he was joint eighth at the 2019 PGA Championship.
He was still not certain of a place at Royal Portrush at that point. However, having already tied for second in both the Commercial Bank Qatar Masters and Hassan Trophy, his spot for the 2019 Open was secured off the DP World Tour rankings and he produced another top-20 performance.
Five weeks later he was celebrating a first Tour victory, closing the Scandinavian Invitation with two rounds of 64 to pip Matthew Fitzpatrick by one, and in November 2019 he was part of a six-man play-off for the Turkish Airlines Open.
His maiden success as a professional came on his home Sunshine Tour in 2017 at the Eye of Africa PGA Championship when he birdied the last and struck an approach to within a foot at the first extra hole to take the three-man play-off.
In February 2020 he tied for third at the WGC-Mexico Championship and in August 2021 he grabbed his first PGA Tour title at the Barracuda Championship. As an amateur, Van Rooyen attended the University of Minnesota before turning professional in 2013.