Rossouw made his first-class debut in November 2007 for Free State against Easterns, batting at number three he topscored in the match with 83, an innings that included 13 fours. At the end of his maiden season he made the step-up to franchise cricket playing three Twenty20 matches for the Eagles.
Rossouw was a regular in the Eagles team during the 2008/09 season, in the SuperSport Series he was the team's leading scorer with 765 runs including three centuries. His maiden first-class century came against the Titans in November 2008, he made 106 including 20 boundaries. In the return fixture in March 2009 he scored 109 in a team total of 178, no other batsman passed 16. Again the innings was in vain as the Eagles lost to the league champions. In the one-day format he also scored a maiden century, he struck 131 off 108 balls against the Warriors.
Rossouw scored 1,261 runs at 57.61 in the 2009/10 season, this included a score of 319 off 291 balls against the Titans. The innings was the fastest triple century in South African domestic cricket and included 47 fours and 8 sixes. Alongside Dean Elgar he shared a second wicket partnership of 480 in 84 overs, the largest South African partnership for any wicket.
Rossouw played in the IPL 2011 for Royal Challengers Bangalore and replaced Nic Maddinson in IPL 2014 for Royal Challengers Bangalore. He was included in the Free State cricket team squad for the 2015 Africa T20 Cup.
Rossouw played in the 2017 Season of the Pakistan Super League for the Quetta Gladiators as a replacement player. Where it was reported that he earned around $370,000. He will play for Khulna Titans in BPL 2017.
While attending Grey College in Bloemfontein Rossouw was selected to represent a South African schools team. He made his debut for South Africa under-19s in the second 'Test' against Bangladesh in December 2007. He also played against India prior to the 2008 U/19 Cricket World Cup. At the World Cup he played all six matches scoring 136 runs at an average of 34.00 as South Africa reached the final.
Roussow was selected in the South Africa A squad for the tours of Bangladesh and Sri Lanka in 2010, on the latter he scored 131 from 151 balls against Sri Lanka A, sharing century stands with Dean Elgar and Jonathan Vandiar.
He made his One Day International debut against Zimbabwe in August 2014He was run out on without even opening his account.He couldn't open his account in the second match as well.He scored his first fifty in his 9th ODI.
He made his Twenty20 International debut for South Africa against Australia on 5 November 2014. He was the man of the match for his score of 78 off 50 balls.
On 5 January 2017, Rossouw signed a Kolpak deal with Hampshire County Cricket Club which made him ineligible to represent South Africa anymore, ending his international career. His last act as an international cricketer was to incorrectly spell the name of his coach Russell Domingo as Russel Domingo in his resignation mail sent from his mobile phone.