Postecoglou will have just a handful of friendlies to turn an ageing team which looked spiritless in recent 6-0 defeats to both Brazil and France into a side that can do Australia proud in their third successive finals campaign.
The 48-year-old conceded taking charge of the side - ranked 57th in the world - was a "challenge", but radiated optimism that he could build a team that would not only do credit to football but the whole of Australian sport.
"My hope and my belief is that we can restore pride to the national team and our national team jersey," he said after his unveiling.
"I really want to sell hope to people who love football, but more importantly, love our nation.
"You look across all our codes and national teams, we want them to do well and not many of them are at the moment.
"So there is a great opportunity for us to be a flag bearer there."
Postecoglou built his reputation by overhauling a Brisbane Roar squad and leading them to successive A-League titles in 2011 and 2012 before starting a similar rejuvenation project at the Melbourne Victory.
The clock is ticking in the run-up to the World Cup, though, and Postecoglou said the process would be more gradual at the Socceroos with no wholesale clear-out of his thirtysomethings like skipper Lucas Neill and goalkeeper Mark Schwarzer.
"Wherever I've gone people see the way I've worked and have seen that I like to make informed decisions, I won't be going in there with any preconceptions," he said.
"I've got my idea about how I'd like the team to play and how I want the environment structured ... and then we'll find out who fits in there.
"I'm not going in with a target or a hit-list of people, that's not the way I work. Sometimes people surprise you. I certainly don't discount anyone. But will there be changes? Of course there will."
If the five-year deal he was handed on Wednesday was an indication of the faith Football Federation Australia have in him to deliver, Postecoglou was emphatic that he would ultimately be putting his own trust in youth.
"I think we need to expose some of our younger players to international football and find out who can and who can't play at that level," he said.
"I have never been let down by throwing young players in and you never really find out until you give them the opportunity. I plan to do that."
Although Postecoglou's overseas experience at club level was limited to a short stint at tiny Greek club Panachaiki, he describes his seven years in charge of the national youth team as his "PhD in coaching".
In 17 years as a coach, he has garnered a reputation for building teams that play an adventurous style of football and he saw no reason to alter his philosophy with the national team.
"I'm sitting here because I've always followed my beliefs in the way a team should play and that won't change now," he said.
"I think we need to start taking some ascendancy here in Asia in the way we play our football.
"Particularly here at home, I'd like us to play an attacking and aggressive type of football because that's what the Australian public like and I think that's the way modern football is going anyway.
"It's not just about the aesthetics, I'm very much into winning. I've full faith that Australian footballers can play the modern style of game."
Those comments that will certainly gladden the hearts of Australians, who suffered through some laboured performances in the last couple of years of Holger Osieck's reign as coach.
The German's summary dismissal after the humbling in Paris earlier this month, despite having led Australia to qualification for Brazil, was a stark reminder of the price of failure, even in friendlies.
"There are no guarantees in life," the FFA's billionaire chairman Frank Lowy said when asked if Postecoglou would be given time to complete his project.
"In football there are no guarantees. We know the ball is round and there are lots of other things that can happen."