The Australian revealed the Scottish champions wanted him to extend his stay in Glasgow but the “new opportunity” presented to him was one he wanted to explore after two seasons at Celtic Park. The club confirmed “the process of appointing” his replacement is “already underway” but told fans that while they want to appoint a manager as soon as possible the “priority will be to appoint the best candidate to take the club forward”.
Postecoglou leaves big shoes to fill following a hugely successful two-year spell having taken over from Neil Lennon after the club missed out on ten in a row. The 57-year-old won five trophies, including two Premiership titles and the treble this campaign, during his time, while creating a style of play which excited fans and had huge success in the transfer market.
The new Celtic boss is set to encounter a rejuvenated Rangers who finished seven points behind in the league and lost to their rivals in the League Cup final and Scottish Cup semi-final. Michael Beale has already started his promised summer rebuild, while Postecoglou revealed in the aftermath of the Scottish Cup final win that some of the champions' stars could depart. They will, however, once again start in the Champions League group stage following the Premiership win.
Speculation is well and truly underway as to who replaces Postecoglou with a number of familiar names in mentioned, while former Celtic defender Alan Stubbs noted the club are “in a very strong position now and I think there will be big names from across Europe who would be very interested”.
We look at 13 possible candidates for the job...

. GLASGOW, SCOTLAND - MAY 11: A general view during a Park's Motor Group Scottish Women's Premiership League match between Celtic and Glasgow City at Celtic Park, on May 11, 2023, in Glasgow, Scotland. (Photo by Craig Foy / SNS Group)
Celtic's search for a new manager is underway. (Photo by Craig Foy / SNS Group) Photo: Craig Foy - SNS Group

. Martin O’Neill - 25/1
A Celtic hero from his five-year spell as manager between 2000 and 2005. Won seven trophies, including a treble and took the team to the UEFA Cup final. Now 71, his last managerial role was a short stint at Nottingham Forest four years ago. Photo: Craig Williamson - SNS Group

. Neil Lennon 25/1
Celtic turned to Lennon when Brendan Rodgers departed midway through the 2018/19 campaign. He carried on the work done by the Northern Irishman and won a treble of his own the following season before things unravelled in 2020/21. A third spell as Celtic boss is unlikely. Photo: Craig Williamson - SNS Group

. Steve Clarke - 20/1
Has done a fine job as Scotland national team boss, taking the team to Euro 2020 and the qualifying campaign for Euro 2024 is off to a flyer with wins over Cyprus and Spain. Ahead of those matches he signed a deal until 2026. Photo: Paul Devlin - SNS Group

1. Martin O’Neill - 25/1
A Celtic hero from his five-year spell as manager between 2000 and 2005. Won seven trophies, including a treble and took the team to the UEFA Cup final. Now 71, his last managerial role was a short stint at Nottingham Forest four years ago. Photo: Craig Williamson - SNS Group

2. Neil Lennon 25/1
Celtic turned to Lennon when Brendan Rodgers departed midway through the 2018/19 campaign. He carried on the work done by the Northern Irishman and won a treble of his own the following season before things unravelled in 2020/21. A third spell as Celtic boss is unlikely. Photo: Craig Williamson - SNS Group

3. Steve Clarke - 20/1
Has done a fine job as Scotland national team boss, taking the team to Euro 2020 and the qualifying campaign for Euro 2024 is off to a flyer with wins over Cyprus and Spain. Ahead of those matches he signed a deal until 2026. Photo: Paul Devlin - SNS Group

4. Lucien Favre - 20/1
The former Swiss international is hugely experienced having managed in France, Germany and his homeland, including notable spells with Borussia Dortmund, Borussia Monchengladbach and two stints with Nice, the latest coming to an end in January. Photo: SNS Group Rob Casey