Upon moving to the Griquas in 2012, Le Roux was instantly called up to the Cheetahs Super Rugby squad. He made his debut in Week 1 of the 2012 Super Rugby season as a half-time substitute for Dusty Noble as the Cheetahs lost 25-27 to the Lions in Johannesburg. Despite this early setback Le Roux went on to have an excellent first season in Super Rugby, playing mostly on the wing he scored 7 tries in 16 appearances. His second season proved even more successful as he helped the Cheetahs reach the play-offs with a further 6 tries in 17 matches.
In July 2013, it was announced that Le Roux had signed a new contract with the Cheetahs until the end of 2015, which also meant that he would play for the Free State Cheetahs domestically from 2014 onwards.
He left the Cheetahs after the 2015 Super Rugby season to spend some time playing in Japan with Canon Eagles before joining the Sharks for 2016.
In August 2016, English Premiership side Wasps announced Le Roux would join them in January 2017 after finishing his commitments with the Canon Eagles. He left Wasps in 2019 having played 46 games and scoring 50 points.
On 5 May 2019 Le Roux returned to Japan to sign for Toyota Verblitz in the Top League from the 2019-20 season.
On July 4, 2023, Le Roux returned to South Africa to join the Blue Bulls, where he began playing after the Springboks world cup campaign. He made his debut on the 25 November 2023 against Connacht in the United Rugby Championship where he scored one try in there 53-27 win.
Le Roux was selected to represent the Springboks for the first time during the South African Quadrangular tournament of 2013 against Italy, Scotland and Samoa. He played the full 80 minutes of all three test matches against these teams with distinction, hardly faltering any time at full-back, and contributed to the try-making by joining the Springbok backline in sprints for the opponents' tryline.
He also played an integral part in South Africa's 2013 Rugby Championship campaign, featuring in all six matches. He scored tries in both home and away tests against Australia and in the deciding game at home to New Zealand.
Le Roux started the 2013 end-of-year tests on the bench for the match against Wales, however an injury to starting fly-half Morne Steyn saw him enter to the fray as an early substitute in the full-back position. It was a position he was to retain for the remaining two tour matches. He turned in a particularly impressive display in the 28-0 destruction of Scotland scoring one intercept try and setting up another immediately from the restart for team-mate JP Pietersen.
On 14 June 2014, Le Roux produced a man-of-the-match performance to help South Africa beat Wales during the 2014 incoming tours, scoring a try and providing three assists.
In 2014, he was one of five nominees for the IRB Player of the Year award.
Le Roux was named in South Africa's squad for the 2019 Rugby World Cup. South Africa went on to win the tournament, defeating England in the final.
Le Roux was named in South Africa’s 33 man squad for the 2023 Rugby World Cup. South Africa went on to win the tournament, defeating New Zealand in the final. He is one of 43 players who have won the Rugby World Cup on multiple occasions, 25 of whom are South Africans