Brabec was part of the
youth system at
Sparta Prague, but having been released in summer 2008, he joined
Viktoria Žižkov, another
Prague-based club. He was promoted to the Žižkov first team during the
2008–09 Czech First League season, when he was still at school. He made one league appearance for the club in this season, playing a full match against
Viktoria Plzen as a 16-year-old in a 2–0 defeat. In the
2009–10 season, Brabec played a further 14 games for Žižkov, who were then playing in the second tier
Czech 2. Liga. One of the fourteen appearances was as a substitute. In one match in this season against
FC Zenit Čáslav, he received a 31st-minute red card. He told
UEFA.com that his primary motivation for making the transfer was that he was a childhood fan of his former club and that he would have a better chance of playing in the
UEFA Cup and the
Uefa Champions League. He started the 2011–12 season with the reserve team, Sparta Prague II, who compete in the 2. Liga. On 31 August 2016, Brabec signed a four-year contract with
Genk.
Aris On 31 August 2021,
Aris officially announced the signing of Brabec for an undisclosed fee on a three-year contract. On 18 October 2021, he scored his first goal sealing a precious 1–0 away win against
Lamia. On 13 March 2023, Brabec signed a contract extension with the club until summer 2026.
Rio Ave On 8 September 2025, Brabec signed a two-year contract with
Primeira Liga club
Rio Ave. ==International career==