Career
Croatia
After going through the youth ranks of Dinamo Zagreb, Poljak was moved to their feeder team Lokomotiva Zagreb, then playing in the Druga HNL. After a season there he signed a 7-year contract with the club, which was taken over by Dinamo at the beginning of 2010. He spent the next two and a half seasons on loan at NK Lokomotiva, however, before his contract was terminated in the summer of 2012. Western Sydney Wanderers
On 13 August 2012 it was announced that Poljak had signed with the newly formed A-League club Western Sydney Wanderers.
He signed an initial two year contract, set to expire in July 2014.
On 5 September 2013, Poljak signed a two year extension with the club, the new contract ending mid 2016. Poljak again in his second season with Western Sydney was a constant starter throughout with his side finishing the league in second position.
Newcastle Jets
In 2015, Poljak was not retained by the Wanderers and joined Newcastle United Jets Football Club.
