Born in Dandenong, Victoria,[2] Hrustic played youth football with South Melbourne and Schalke 04 before moving to FC Groningen, where he made his professional debut in 2017.

Hrustic scored his first goal for Eintracht Frankfurt against Mainz 05, on 9 May 2021, with an improvised finish where he managed to chip the ball over goalkeeper Robin Zentner.

[17] Due to his Bosnian and Romanian heritage, Hrustic was eligible to represent Bosnia and Herzegovina and Romania internationally, in addition to his birth country Australia.

[22] On 4 June 2021, Hrustic scored his first goal for Australia against Kuwait in the second round of World Cup qualifying, bending the ball off the inside of the post and in from a 30-odd-metre free-kick.

During Australia's cut-throat match against the United Arab Emirates in the fourth round of qualifying, Hrustic scored his third goal with a sweetly struck volley that deflected off a UAE defender in the dying minutes of the match to secure the win for Australia and passage through to the intercontinental play-off round against Peru.

Despite suffering an injury while playing for Hellas Verona and being a doubt for the tournament,[23] Hrustic was included in the 2022 FIFA World Cup squad, being substituted on in Australia's final three matches as the Socceroos were knocked out by Argentina in the round of sixteen.

[24] After a 2–0 friendly loss against Argentina on 15 June 2023, he missed out on the next four Australia squads including the Asian Cup due to lack of playing time at club level.

On 21 March 2024, Hrustic made his first appearance for Australia since the loss to Argentina, playing against Lebanon in the second round of World Cup qualifying.