He came on as a substitute on the hour mark at Olën Park in their 2013 Currie Cup First Division match against the eventual champions, the Pumas.
In April 2014, Van der Merwe was a surprise inclusion in the Lions touring squad for their Australian leg of the 2014 Super Rugby season.
At the conclusion of the 2017 Super Rugby Season Van der Merwe again came off the bench in the final, which saw the Lions defeated by the Crusaders.
Van der Merwe started at hooker as the Sharks fell to the Crusaders at the quarter-finals stage of the competition.
The most notable event of the season came during a Sharks home game against the Bulls, which saw Van der Merwe sent off following an altercation with Springbok hooker Schalk Brits.
[24] Sale Sharks announced in June 2023 that he had agreed early release from his contract and would be leaving the club with immediate effect and return to South Africa.
[2] He is the older brother of Scotland international and British and Irish Lions winger Duhan van der Merwe, who also played Craven Week rugby for SWD Eagles and was included in the South African Schools sides in 2012 and 2013.