Ange Postecoglou is back on top — not that those who believed in him expected anything different.

Nearly a year after his bombshell move from Yokohama F. Marinos to Celtic, the Australian coach has added yet another title to his distinguished resume by winning the Scottish Premiership, clinching the trophy with Wednesday’s 1-1 away draw against Dundee United.

Prior to arriving in Glasgow, Postecoglou’s personal silverware cabinet already featured league championships in Japan and Australia — as well as the 2015 Asian Cup that established him as one of the continent’s brightest talents in the dugout.

Now he has a domestic double in Europe to his credit, having won the Premiership as well as the Scottish League Cup in what many had anticipated would be a rebuilding year for the Hoops.

"If you had told me 12 months ago I'd be standing here — I wasn't even sure I'd be on this continent let alone be manager of this football club," Postecoglou told the BBC. "The dream was always to manage a famous club and try to make an impact. When something is almost a lifelong obsession and you finally get there, it's hard to put into words.

"It almost feels like two seasons in one. We've jammed in a rebuilding season and a season to win. We had a lot of work to do, and with the support of everyone at the club, we got there."

The title comes as joyous relief for Celtic fans who were in despair at the end of last season, sitting at the wrong end of a 25-point gap between themselves and archrival Rangers. But it’s also the ultimate vindication for those who have backed Postecoglou from the start.

The 56-year-old only emerged as a candidate to lead the storied club after Bournemouth legend Eddie Howe turned the job down, leading local media and fans to question whether Celtic was making the right move by approaching someone who many thought to be a complete unknown.

But as he did in Australia and Japan, Postecoglou turned doubters into believers. With characteristically unshakable confidence in his attacking style, he overcame early stumbles — including a narrow defeat to Rangers at Ibrox — and steered Celtic to the top of the table soon after the winter break.

That confidence extended from the technical area to the news conference podium, where Postecoglou deftly deflected jabs from Glasgow’s notoriously antagonistic sports media with his no-nonsense attitude and dry wit — endearing himself to Celtic fans who love nothing more than a fighter wearing their colors.

“Supporters sing songs about him, they parade his face on their social media accounts like a badge of pride, some have even bought up the black jumper he wears from the club shop to wear as a sartorial tribute,” wrote Vince Rugari in the Sydney Morning Herald.

“(His) methods are standing up in Glasgow, through the constant tension and turmoil of the Old Firm rivalry, despite all the predictions that Postecoglou might buckle in that unique environment.”

In Japan, Postecoglou has joined the likes of former Nagoya Grampus and Arsenal manager Arsene Wenger as well as Wim Jansen — who transitioned from Sanfrecce Hiroshima to Celtic and subsequently denied rival Rangers a 10th consecutive championship in 1998 — in an elite fraternity of J. League managers who found European success.

“He was the first to prove that an Asian manager could succeed in Europe,” tweeted freelance journalist Wataru Funaki, who covered Postecoglou closely during his time in Yokohama. “Over the past 4½ years, he has taught us what real football is, what we have to do to win every single game and the importance of believing.”

But perhaps more importantly, Postecoglou’s decision to bring over a quartet of Japanese players — three of whom had a significant impact on Celtic’s title run — has brought new attention to the J. League and potentially given Japanese soccer a boost in preparations for the upcoming FIFA World Cup.

In the space of one season, summer arrival Kyogo Furuhashi and winter signings Daizen Maeda and Reo Hatate have become cult heroes at Celtic Park, each contributing to key results on the pitch — whether it was Furuhashi’s hat trick in his home debut on Aug. 8 against Dundee, Hatate’s double in the Feb. 2 Glasgow derby against Rangers or Daizen Maeda’s equalizer against Hearts on May 7 to assuage concerns of a late stumble.

The three combined for 20 goals and seven assists in the domestic league — figures that are all the more impressive when considering that Furuhashi missed several months with a hamstring injury and how little he and his Japanese teammates have rested since the J. League’s pandemic-impacted 2020 season.

Since June of that year, Furuhashi, Maeda and Hatate have each recorded just over 100 competitive appearances for their clubs and Japan’s senior and Olympic teams — figures exceeded only by Celtic captain Callum McGregor’s 125, according to independent Celtic media outlet The Cynic — and racked up astonishing amounts of time spent traveling between Scotland and Asia for international duty.

They — along with Yosuke Ideguchi, who also arrived in January but made just two league appearances due to injury — will have a full summer to relax and recuperate, a break that will ideally help them to prepare for what is perhaps the biggest prize Celtic clinched on Wednesday: a place in the Champions League group stage for the first time in five years.

The lack of Japanese players in Europe’s marquee club competition has been a major point of concern in recent seasons, with Liverpool’s Takumi Minamino a rare exception. But Celtic’s return will give the four players a chance to test themselves against some of the biggest clubs in the world — as well as make their case to Japan head coach Hajime Moriyasu for inclusion in the Samurai Blue’s squad for Qatar 2022.

“I’m looking forward to seeing how far Postecoglou’s style will go in the Champions League, and it will be an incredibly important experience for the Japanese players,” Funaki told From the Spot.

“If they cause a few upsets, it will be vindication for Postecoglou’s attacking philosophy, and it will show that F. Marinos and the players who worked under him all took the right path.”

While Celtic fans across the world will take the next few days to celebrate — including Saturday’s season finale-turned-coronation against Motherwell — Postecoglou is already looking ahead to the challenges that will face him this fall, declaring this week that he intends to lock down his transfer targets early and go into the preseason with a full squad.

It’s an ethic that is all too fitting for the man known affectionately to his players and fans as “The Boss.” Now, after seeing what he can do in just a year, they’ll be all too excited to watch him get back to work.