In early 2017, he had his first win on the tour, the Eye of Africa PGA Championship, making a birdie at the first extra hole in a three-man playoff.

A number of other good finishes, including fourth place in the Kazakhstan Open and a tie for third in the season-ending NBO Golf Classic Grand Final, put van Rooyen third in the Challenge Tour Race to Oman rankings, earning a card for the 2018 European Tour season.In December 2017, van Rooyen was runner-up in the Joburg Open, three strokes behind Shubhankar Sharma.

Van Rooyen made a good start to 2019, finishing joint runner-up in the Commercial Bank Qatar Masters and the Hassan II Golf Trophy.

On 25 August 2019, van Rooyen won his first European Tour title at the Scandinavian Invitation at Hills Golf & Sports Club, outside Gothenburg, Sweden.

After a T20 finish at the 2020 WGC-FedEx St. Jude Invitational in August 2020, van Rooyen was granted Special Temporary Membership until the end of the 2019–20 PGA Tour season.