He was selected to represent Namibia as early as primary school level, playing at the South African Under-13 Craven Week tournament held in Kimberley in 2009, starting in the scrum-half position[2] and helping them to one victory in their match against Zimbabwe.
[4] He played all their matches at outside centre and he contributed 15 points in their 30–13 victory over Zimbabwe, scoring one try, two conversions and two penalties[5] to finish as his side's top scorer in the tournament.
[6] He again represented Namibia in 2014 in South Africa's premier rugby union competition for high schools, the Under-18 Craven Week tournament held in Middelburg.
[23] Rossouw was included in the Blue Bulls squad for the 2016 Currie Cup qualification series[24] and he made his first class debut in their Round Six match against the Pumas, coming on as a replacement just after the hour mark of a 13–25 defeat.
He was to remain in that position for the remainder of the competition, scoring his first senior try in a 28–23 victory over SWD Eagles[29] and following that up with tries against the Boland Cavaliers[30] and the team from his home country, the Welwitschias.