A product of the Fenerbahce youth system, Mert made his Super Lig debut in a 4-0 win against Antalyaspor in August 2010.
He went on to make over 50 appearances for the club, winning two league titles, before joining fellow top-flight side Bursaspor on a free transfer in July 2015.
A regular in his first season, he remained with the club until the summer of 2017 when he joined Istanbul Basaksehir, making 34 Super Lig appearances during the 2018/19 campaign.
He was first drafted into Turkey’s senior squad in 2012, during his time with Fenerbahce, and made his debut in a 3-1 friendly win against Georgia in May that year.
Mert established himself as his country’s first-choice keeper in ahead of the current European Championship qualifying campaign, making nine appearances in 2019.