He previously played for the Gold Coast Titans, Canberra Raiders in the NRL and the Huddersfield Giants and Leeds Rhinos in the Super League.

Sezer was born in Bankstown, Sydney, New South Wales, Australia to a Turkish father, Yüçel, and an Indigenous Australian mother.

[19] Sezer finished the 2016 NRL season with him playing in 24 matches, scoring 5 tries and kicking 5 goals in his first year with the Canberra club.

Sezer and his halves partner Blake Austin were subjected to criticism at the end of the season for not lifting their game to close out matches and were taking the back seat for hooker Josh Hodgson who did the key playmaking a little too often than they should have.

[27] Sezer started the 2019 NRL season as the club's first choice halfback and kicked a field goal in the opening round as Canberra defeated the Gold Coast 21–0.

In round 24, Sezer kicked 3 field goals in Canberra's 15–14 win against the Cronulla-Sutherland Sharks at Pointsbet Stadium, including the game winner in golden point extra time.

[34] In round 5 of the 2021 Super League season, Sezer scored two tries and kicked two goals as Huddersfield defeated Leeds 14–13 to claim their first win of the year.

On 19 July, it was announced that Sezer would leave Huddersfield at the end of 2021 to take up a two-year deal with eight time Super League Champions Leeds.

[39] Sezer played a total of 19 games for Leeds in the 2023 Super League season as the club finished 8th on the table and missed the playoffs.

[41] In round 9, Sezer was placed on report but not sin-binned for a supposed hip-drop on Joshua Curran in the Tigers' 22-14 loss against the Canterbury-Bankstown Bulldogs.

[44] Sezer played 17 games for the Wests Tigers throughout the 2024 NRL season as the club finished with the Wooden Spoon for a third consecutive year.