Van Rensburg represented the Blue Bulls at the Under-16 Grant Khomo Week in 2010 and then again Under-18 Craven Week in 2012.
In 2013, he was included in the Blue Bulls Under-19 squad for the 2013 Under-19 Provincial Championship and made a total of nine appearances, including the final of the competition.
He was selected in the South Africa Under-20 squad that participated at the 2014 Junior World Championship and started in all five their matches during the competition which saw South Africa qualify for the semi-finals.
Van Rensburg moved to France in 2016 to join Top 14 side Montpellier.
As of March 2020, he has made 66 appearances for the French club, scoring 45 points.
Janse van Rensburg helped Montpellier to the Challenge Cup title during the 2020/21 season.
June 2021 saw him being named in South Africa's 46-man squad for the British and Irish Lions Tour. He turned out for the South Africa A team who managed a 17-13 victory over Warren Gatland's charges.
He made his test debut off the bench in South Africa's opening game of the 2021 Rugby Championship against Argentina.
JW August 2021.
Career
 |
Montpellier No 5 Lock |
2016 - present |
 |
South Africa U20's No 5 Lock |
2014 - 2016 |
 |
Bulls No 5 Lock |
2014 - 2016 |
 |
Blue Bulls No 4 Lock |
2014 - 2016 |
 |
South Africa A No 5 Lock |
2021 - 2021 |
 |
South Africa No 5 Lock |
2021 - 2024 |
