A product of Afrikaans Hoer Seunskool (Affies) in Pretoria, Steyn van der Spuy first represented the Blue Bulls at the U13 Craven Week of 2013, whilst also earning national colours for Athletics as a distinguished hurdler. Turning out for his provincial Sevens team in the same year, van der Spuy continued to exhibit all the x-factor that impressed coaches and onlookers alike, earning selection once again for his province at the U16 Grant Khomo Week of 2016 and enjoying a two-year spell in the incredibly powerful Affies 1^st XV. An accurate goal-kicker with an impressive range, his natural athleticism has seen Steyn turn out at both wing and flyhalf, but he is most comfortable as a commanding halfback.

Blessed with an ability to visualize multiple phases, peg back opponents with accurate tactical kicks and controlling the general pace of the game, van der Spuy is renowned for his excellent ball handling and the consistency of his pass. He once again showed his raw talent on a national stage at the U18 Academy Week of 2018, after which Steyn decided to remain in Pretoria by signing a junior provincial contract with the Blue Bulls. He played a valuable role in their championship winning U19 Currie Cup campaign of 2019.