Rossouw made his provincial debut during 1999 for the Blue Bulls in a match against the North Western Province in the Currie Cup competition.

Rossouw made his first international appearance in the Springboks' opening pool game against Uruguay at the 2003 Rugby World Cup in Australia.

Rossouw was picked as first-choice Number 8 for the Springboks in their successful world cup campaign of 2007.

This was a result of Pierre Spies' unfortunate illness, however Rossouw would no doubt have featured in the squad regardless.

However he recovered and played an important part in the rest of the Springboks march to victory, including a try-saving tackle on Mark Cueto in the final.