Early career Born in
Bursa, he lost his father when he was only 9 years old. His father was also an amateur football player and in an interview, he said that he grew up in a family that loved football and that he promised his father to be a football player when he was little. He spent part of his youth in Bursa Güven and Yeşil Bursa and his first season as a senior in amateur football. Mert Hakan made his first professional contract with
Altınordu. In the 2014–15 season, he loaned to
Tire 1922. He made a very strong start with new coach
Taha Evke in there and became one of the key players who took more responsibility on the field, He made his professional debut for Sivasspor in a 2–0 Süper Lig win over
Yeni Malatyaspor on 19 August 2017. On 21 September 2017, he scored his first goal with the team against
Bugsaşspor in a 3–0 win
Turkish Cup match.
Fenerbahçe On 11 August 2020, he transferred to
Süper Lig powerhouse
Fenerbahçe on a free transfer, signed four years deal. On 21 September 2020, he made his debut in a 0–0 tie against
Hatayspor in
2020–21 Süper Lig season. On 21 November 2020, he scored his first goal against
Gençlerbirliği in
Süper Lig match, netting the first goal in a 5–1 away game victory. In the 2021–22 season, he became
vice-captain of the team after
Altay Bayındır and
Mesut Özil. On 16 September 2021, he made his continental debut in his career against
Eintracht Frankfurt in
UEFA Europa League away game which finished 1–1. On 4 November 2021, he captained first time of the team in
UEFA Europa League match, 3–0 win against
Royal Antwerp and also scored a goal from outside the box. On 21 June 2024, Fenerbahçe extended his contract for two years. On 16 February 2025, he made his 100th
Süper Lig appearances for Fenerbahçe against
Kasımpaşa in a 3–1 home win. On 5 August 2025, he became
captain of the team. ==Betting investigation==