Bence Mervó

On 31 May 2014, Mervó made his first appearance for Győr on the 30th match day of the 2013–14 Nemzeti Bajnokság I season against Mezőkövesd at ETO Park, Győr, Hungary. In the 2014–15 Nemzeti Bajnokság I season, he made five more appearances for Győr.

Sion

In 2015, Mervó was signed by Swiss Super League club Sion. He made no appearances during the 2015–16 Swiss Super League season.

Śląsk Wrocław (loan)

On 29 February 2016, he was loaned to Polish Ekstraklasa club Śląsk Wrocław. On 9 April 2016, he scored his first goal in the 70th minute against Cracovia on the 30th match day of the 2015–16 Ekstraklasa season at the Stadion Miejski, Wrocław, Poland. The match ended with a 2–1 victory for Śląsk. On 20 April 2016, he scored a double, in the 14th and 35th minute, in a 3–1 win over Jagiellonia Białystok on the 2nd match day of the 2015–16 Ekstraklasa play-off.

Szentlőrinc

After playing for Szentlőrinc on loan in the previous two seasons, on 18 July 2022 Mervó moved to the club on a permanent basis, signing a two-year contract.

He was part of the Hungarian U19 at the 2014 UEFA European Under-19 Championship and the U20 team at the 2015 FIFA U-20 World Cup.

Hungary U21

On 1 September 2016, he scored a double against Liechtenstein in the 2017 UEFA European Under-21 Championship qualification match at Ménfői út.