Toma Bašić went through the ranks of NK Zagreb, before signing for Hajduk Split in the summer of 2014, the same generation as Fran Tudor.

He made his first team and Prva HNL debut on 10 August 2015 in a 1–2 away win against Lokomotiva, coming in for Andrija Balić in the 84th minute.

[6] On 19 December, he scored his first goal for the club, in a Coupe de la Ligue game against Dijon that ended in a 1–0 victory.

[11] Bašić was selected to Nenad Gračan's 23-man squad for UEFA Under-21 Euro 2019, remaining an unused substitute throughout the tournament as Croatia finished last in their group.

[16] Bašić was born and raised in the Dubrava neighborhood of Zagreb, and was a fan of Hajduk Split through his father, who is originally from Pirovac in Dalmatia.