Fulham has signed midfielder
The veteran, who has also played for Inter Milan and Benfica, will help to fill the void left at Fulham by the departures of Clint Dempsey and Mousa Dembele to Tottenham Hotspur.
Karagounis told his new club's official website, www.fulhamfc.com: "I'm delighted to have signed for Fulham Football Club and I am excited by a new challenge in England and the Barclays Premier League.
"I'm looking forward to working under Martin Jol and playing alongside some fantastic players at this club."
Manager Jol added: "Giorgos Karagounis has a wealth of club and international experience and I'm happy that he's joined us for this season.
"He's been an influential player for his club sides and is a renowned player in world football as he's about to become the most-capped player for Greece.
"He brings many certain qualities to our squad."
EURO 2012 saw Karagounis earn a record-equalling 120th cap for Greece before missing the outright record after being controversially suspended for its quarter-final defeat to Germany.
He has not played for his country since and was left out of the squad for its opening 2014 FIFA World Cup qualifiers this month, ostensibly because he was without a club.
Long-serving Brisbane Roar midfielder Massimo Murdocca has been granted a release to return to his family in the Victorian capital and link up with Melbourne Heart.