After representing the Sharks in the 2006 Under-13 Craven Week competition, he moved to Ermelo and subsequently represented the Pumas at the 2009 Under-16 Grant Khomo Week and 2011 Under-18 Craven Week tournaments. His performance in the latter tournament led to his selection in the 2011 South African Schools squad.[2]
In 2012, he joined the Blue Bulls and made twelve appearances for them in the 2012 Under-21 Provincial Championship competition.[3]
Du Plessis made his senior debut for the Blue Bulls in 2013, starting in the 110–0 thrashing of the Limpopo Blue Bulls.[4] He also started the game the following week in an equally impressive 89–10 victory against the Griffons,[5] a match that saw him score his first try, dotting down shortly after half-time.
In July 2013, the Blue Bulls announced that he signed a contract extension until 31 October 2015.[6]
In July 2013, Du Plessis was named on the bench for the Bulls' Super Rugby match against the Stormers[7] and came on as a substitute to make his Bulls debut.[8]
Du Plessis was included in the Bulls squad for the 2014 Super Rugby seasonto resign[9] and made his Super Rugby start in a 31–16 defeat to the Sharks in Durban.[10][11]
Shortly before the 2015 Super Rugby season, the Bulls announced that Du Plessis would leave after the 2015 Currie Cup Premier Division to take up a two-year contract with French Top 14 side Montpellier.[12]
On 12 April 2021, Du Plessis has left Montpellier early to return to South Africa with the Bulls.[13]
Du Plessis was included the South Africa Under-20 squad for the 2013 IRB Junior World Championship.[14]
In May 2014, Du Plessis was one of eight uncapped players that were called up to a Springbok training camp prior to the 2014 mid-year rugby union tests.[15]
Du Plessis also played some Varsity Cup rugby, representing the UP Tuks in the 2013 Varsity Cup competition.[16]
