 Rousseau ndiye akabata rekodhi yeSouth Africa mumakwikwi e400m Individual Medley LCM nenguva ya 4:11.11, iyo yaakawana paakakunda mutambo uyu mu2013 US Open. Akakwikwidza mu2009 uye 2011 World Swimming Championships, muRome neShanghai zvichiteerana. Akakwikwidza mumitambo yeCommonwealth ya2010 na2014, muDelhi neGlasgow zvichiteerana. Akakwikwidza mumakwikwi e4 × 200 metres freestyle relay mumitambo yeOlympics ya2008 uye mumakwikwi e4 × 200 metres freestyle relaypamitambo yeOlympic ya2012. Pa2014 Commonwealth Games, akahwina menduru dzebronze mumakwikwi e400m ega ega, 200m butterfly, 4 × 200 m freestyle relay uye 4 × 100 m medley relay. Mumitambo yeOlympics ya2016, akakwikwidza mumakwikwi e400 m ega ega kwaakapedza 21st mumakwikwi ekupisa nenguva ye4:18.72 uye haana kukwanisa kuenda kumagumo. Akakwikwidzawo mumakwikwi e200 m butterfly kwaakapedza ari wechi23 mumakwikwi aya aine nguva ye1:57.33 uye haana kukwanisa kuenda kuma semifinals. Akanga ari chikamu cheSouth Africa 4 × 200 m freestyle relay team iyo yakapedza 10th mu heats uye haina kukwanisa kusvika kumagumo. Rousseau akasiya makwikwi ekushambira zvichitevera Mitambo yeOlympic yeRio muna 2016. 