Australia coach Ange Postecoglou announced on Wednesday that Jedinak would lead his relatively inexperienced side in Brazil.
Postecoglou, who was only installed as Australia's coach in October after Holger Osieck was sacked, has embarked on a rebuilding program ahead of Brazil 2014 to develop the Socceroos for the 2015 AFC Asian Cup and the 2018 World Cup.
And with Jedinak one of only six players with more than 30 caps for Australia - and the sole Australian who regularly plays for a club in a top European league - the defensive midfielder was the obvious choice to captain the Socceroos at the World Cup finals.
Tim Cahill and Mark Bresciano will serve as vice-captains underneath Jedinak.
"Mile Jedinak embodies everything that is great about Australian football and Australia as a nation," Postecoglou said in a statement released by Football Federation Australia.
"He has risen to the top of world football and done it the hard way from humble beginnings where he has battled and believed in himself to overcome the odds with an enormous work ethic and passion for what he does.
"I have no doubt he will lead the team with distinction in Brazil and we will have two of our greatest-ever football players in Tim Cahill and Mark Bresciano giving the team what I believe is strong leadership."
Jedinak only became a professional footballer at the age of 22, when he signed for Central Coast Mariners in the A-League, and claimed he was still getting used to representing his country, let alone leading the national team.
"To be handed the responsibility of captaining my country at the World Cup is humbling, yet incredibly exciting," Jedinak said.
"Just pulling the Socceroo shirt on fills me with pride but to be leading out my country and these players at the World Cup on behalf of all Australians is special."
The 29-year-old made his international debut in 2008 and has played 43 matches for Australia, scoring four goals.
After helping Central Coast win the A-League premiership in the 2007/08 season, the Sydney-born midfielder moved to Genclerbirligi and spent four seasons in Turkey's Super Lig, before joining Palace in July 2011.
Jedinak has made 119 appearances for Palace and was vital to the London-based Premier League club's drive up the table under Tony Pulis in the second half of the recently completed season.
The powerfully built defensive midfielder, who stands at 188cm tall, led the Premier League in interceptions and clearances.
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