Ömer Sismanoglu

Sismanoglu joined St. Pauli on 1 July 2007 on a free transfer. Şişmanoğlu made his debut for FC St. Pauli on 14 December 2007 against FSV Mainz 05.

On 23 June 2009 he left FC St. Pauli and signed a 4-year deal with Kayserispor. He played his first match against Gençlerbirliği in August 2009. He started his first match for Kayserispor against Bursaspor on 6 December 2009. In that game, he scored his first league goal. In the 2009-10 season, he played in 25 matches and scored 7 goals. The highlight of that season was the match against Bucaspor in which he scored 2 goals.

He was sent out on loan to Antalyaspor on 5 September 2012. In the 2012-13 season, he scored 14 of Antalyaspor's 29 goals in all competitions. Şişmanoğlu also scored 6 of those goals in 5 matches in the Turkish Cup. On 1 July 2013, Antalyaspor purchased Sismanoglu from Kayserispor for £450,000.

Just 5 days after signing for Antalyaspor, he moved to Besiktas for £1.49 million. He scored on his debut for Besiktas against Eskişehirspor, which ended 1–0 in favor of Beşiktaş, on 5 October 2013.

On 4 August 2014, Sismanoglu was sent out on loan to Eskişehirspor for the 2014-15 season. He played 22 times in the league, scoring 9 goals. His first goal came on 26 October 2014 in a 4-2 loss to Mersin İdmanyurdu. His goal was the opener on the day, coming in the third minute. His side would go 2-0 up, but concede once in the first half, and three times in the second.

After returning from his loan to Eskisehirspor, he was loaned out again, this time to Konyaspor, on 28 August 2015. He played 11 times in the league, but never found the net. His league debut came on 27 September 2015 in a 2-0 win against Mersin İdmanyurdu. He assisted on Samuel Holmén's 85th minute doubler, having come on off the bench only 14 minutes earlier.

On 18 January 2016, his loan was terminated with Konyaspor and he was sent out again on loan again to Antalyaspor. In 10 league matches with his former club, the striker scored 6 goals.

On 7 August 2017, after returning from his loan to Antalyaspor, Sismanoglu was sold to Goztepe S.K. on a free transfer. His first league goal came on 14 October 2017 in a 3-1 away win against his former club Antalyaspor. That goal came in the 92nd minute of the match, a third for his side. It was an immediate impact, having being brought on for Adis Jahović just five minutes earlier.