He was transferred to Trabzonspor from Sivasspor in January 2010 transfer window. His debut in Turkish football scene was with Vestel Manisaspor in 2003–04. He appeared in 8 matches for Manisaspor but he could not score. Then he returned to Germany to play for the amateur side Berlin Ankaraspor Kulübü 07 since he was out of favor at Manisaspor, and Manisaspor were unwilling to let him out of his contract.
He played two years in amateur division in Germany. After a short stint with SV Yeşilyurt he was transferred to Karşıyaka SK, a football team in İzmir. After a while the team did not pay his salary.Therefore,he left the team. Finally, Sivasspor signed Sezer where he began to shine and had 2 consecutive seasons where he and his teammates played the top of the table, missing the champion's trophy narrowly twice. After his successful Sivasspor adventures, in January 2010 Trabzonspor bought Sezer for a fee of €330,000.