[3][4] He made his professional debut for Hertha BSC in the Bundesliga on 7 November 2020, coming on as a substitute for Dedryck Boyata in the second minute of second-half stoppage time against FC Augsburg, which finished as a 3–0 away win.
[11][12] On 12 March 2024, Dárdai received his first call-up to the Hungarian national team ahead of friendy matches against Turkey and Kosovo.
[13] On 22 March, he came on as a substitute for Botond Balogh in the 67th minute of the match against Turkey at the Puskás Aréna, gaining his first senior international cap.
[14] Four days later, he made his first start for the team, playing the full 90 minutes in central defence as Hungary beat Kosovo 2–0.
[16] In the team's opening match of the tournament, he came on as a 79th minute substitute for Attila Szalai as the Magyars were beaten 3–1 by Switzerland in Cologne.