Born and schooled in George, South Africa, van der Merwe made two appearances for Pretoria Super Rugby franchise, Blue Bulls, after playing for the club’s U19 and U21 sides before making the move to the northern hemisphere.
Van der Merwe wing also represented South Africa at U20 level in the 2014 Junior World Championship. He is the brother of Lions hooker Akker van der Merwe.
The Springbok age-grade internationalist joined French Top 14 club Montpellier on an Academy deal in July 2016, and went onto make three league appearances for the senior side, crossing the whitewash on each occasion.
In May 2017, Duhan signed for Edinburgh Rugby until at least May 2019 and extended his deal in February 2018.
As of the 2018/2019 Champions Cup, van der Merwe has had 4 European Cups appearances scoring 2 tries and 10 points.
|2017 - present|
|South Africa U20's
|2014 - 2017|
|2016 - 2017|