The rise of the former Socceroos boss to become the first Australian manager in the English Premier League has been meteoric.
His challenge to turn Tottenham into a title-winning club looms as the largest of his life.
Postecoglou fronted a huge media pack on Monday ahead of his first game as Spurs manager, a friendly against fellow EPL outfit West Ham in Perth on Tuesday night.
The 27-minute press conference covered an array of topics, from the future of England captain Harry Kane, to how Postecoglou plans to win over the club's fans with an attacking - and successful - brand of football.
But it was the final question that struck the biggest chord.
When asked what his father Jim, who died in 2018, would have thought about his son landing one of the biggest jobs in English soccer, Postecoglou cracked a wry smile.
"Don't stuff it up, mate," he replied.
"I've said before, he's been the greatest influence on my life, he still is. He's not around anymore.
"He was also a hard man, hard to please.
"(He would) pat me on the back but give me a smack on the head as well to make sure I stayed focused on what's important.
"He always said, 'you do these things for other people', and I'm doing it for my family now, my boys and my wife and all those people.
"My dad, my mum - I had a really happy childhood. I know they were working hard to make sure that I didn't realise just how tough it was for us as a family."
Success has followed Postecoglou wherever he's gone.
From Brisbane Roar, to the Socceroos, to Yokohama F Marinos in Japan and more recently Glasgow giants Celtic, Postecoglou's path has been littered with trophies, including Scotland's domestic treble last season.
But the challenge at Tottenham is by far the steepest of his coaching career, and he's embracing the pressure.
"This is a massive football club. It's got a following all over the world," Postecoglou said.
"It's got a glorious history. And when you take a position here, you're excited but also understand there's a massive responsibility there for me to bring success here.
"I think my major barometer would be our fans. If our fans are happy at the end of the year, we've done a good job."
Spurs' list of recent managers includes such luminaries as José Mourinho and Mauricio Pochettino, as well as Antonio Conte and Nuno Espírito Santo.
It's a tough act to follow for Postecoglou, who faces a major task to gain acceptance from the north London club's success-starved supporters.
A group of fans started a #NoToPostecoglou hashtag when whispers emerged that he could become Tottenham's next manager.
Tottenham finished eighth in the EPL last season, in which then-manager Conte labelled his players selfish.
Not since their 11th-placed finish in 2007/08 and eighth-placed finish a year later have they endured such a poor campaign.
One of Postecoglou's main tasks will be ensuring the culture within the club becomes a strength.
Another concerns the future of England captain Harry Kane, who is being heavily linked to German powerhouse Bayern Munich.
Postecoglou is still unsure whether Kane will stay, and says he won't be pressuring the star striker into a quick decision.
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