With just a clutch of domestic and Under-19 matches to his credit, Roelof van der Merwe marked his Twenty20 international debut for South Africa with a quickfire 48 and 1 for 30. He was duly named Man of the Match. It marked a quick rise for a tidy left-arm spinner who can hit the ball hard.

van der Merwe played in the 2004 Under-19 World Cup before he made his domestic debut in 2006 for Northerns, scoring a duck, and the rest of his playing time that season was rather bland. But when he moved to franchise cricket with the Titans for the 2007-08 season, he found success. van der Merwe topped the wickets tally in the MTN Domestic Championship and finished third in the Standard Bank Pro20 Series, contributing handy run in both tournaments. The Titans won both titles and van der Merwe was named Player of the Year, MTN Domestic Championship Player of the Year, Standard Bank Pro20 Series Player of the Year and the Newcomer of the Year for the Titans. He was later named Domestic Newcomer of the Year at the SA Cricket awards. The following season van der Merwe's 30 wickets were pivotal as the Titans retained the MTN Domestic Championship.

van der Merwe was then picked up for South Africa's two Twenty20 matches against Australia in March 2009 and was catapulted him into the big lights. There was also a contract for the IPL's Bangalore franchise, the Royal Challengers.