Career
Early career Šišić began his professional footballing career in Slovenia with NK Rudar Velenje in 2001. In 2003, Šišić signed with Ilisiakos F.C. in Greece. After one season with Ilisiakos, Šišić"s career continued to progress in Greece.
Šišić moved on to Larissa and then Levadiakos (with a short loan spell at Iraklis, and, after a strong start to the 2007-2008 season with Levadiakos, Greece"s most successful club, Olympiacos swooped for the Slovenian winger.
Olympiacos Greek Super League: 2007-2008 Greek Cup: 2007-2008 Red Star Belgrade In 2007-2008, Šišić played under Greek manager Takis Lemonis, and, after Lemonis was sacked in March 2008, Spanish manager José Segura. In the summer, Segura was replaced by another his countryman Ernesto Valverde.
Šišić found playing time difficult to come by under Valverde, and by the winter he had not made a league appearance. During the winter transfer period, Šišić and Olympiacos decided to part ways, and the Slovenian signed with Serbian giants Red Star Belgrade Šišić made his league debut with Red Star in February 2009 in a derby against Partizan Belgrade.
In total, Šišić made 12 appearances for Red Star during the second half of the 2008-2009 season.
Proceedings of the Aristotelian Society Giannina In January 2010, Šišić returned to Greece, signing for Super League club Proceedings of the Aristotelian Society Giannina. Šišić made 15 appearances and scored 2 goals for Giannina during the second half of the 2009-2010 season. Soon after being signed by Olympiacos, Šišić was called up to the Slovenia national team
He scored his first goal in only his second cap—the only goal in a 1–0 victory against Hungary.
He scored his second from the penalty spot in a friendly loss to Croatia. In 2008 and 2009, made 5 appearances (all) starts in 2010 qualification matches, helping Slovenia qualify for the 2010.
