The Australian was reduced to a watching and listening brief for the vast majority of the midweek event but he remained by far the most popular man in the room. Supporters queued up to meet their manager after grilling the board over a number of contentious issues.
The boardroom is not his domain.
"My AGM and my boardrooms are the training pitch and every match day,” Postecoglou said ahead of the semi-final at Hampden Park.
He knows he will be judged, positively and negatively, by what happens on the pitch.
Celtic CEO, Michael Nicholson, said on Wednesday the “club is not broken”. There is a strong argument that it was. Until the arrival of Postecoglou.
"From my perspective I think I was brought in to kind of look ahead and bring my own sort of expertise and views to what we are trying to create,” he said.
"I said from the start that my first task was to assess what was here and what we needed to improve. I think my actions probably speak louder than any words.
“We are slowly building something here. We’ve had to change the playing squad a fair bit. Some because of just natural progression, others because we needed to bring in some different types of players.
"Staff-wise I’ve got the same staff as last year but I’m adding to it, adding good people to it, which we will continue to do. That’s where I lay my marker down.
"I think we have made some progress but we also know there is plenty to be done to get to where we want to.”
You can’t take years to build a team
The idea that Postecoglou needs three or four transfer windows to get his squad in place is something he was keen to play down, noting the demands of the club means results and development need to go hand-in-hand.
“That’s an evolving piece,” he said. “There is no doubt we need to bring in and supplement some more in January. That will be dependent on the progress of the team.
"I’m not putting timelines on it. I knew full well that from my perspective we had to make an impact from the moment I started.
"This is not a football club where you can take two or three years to build a team. You have to do it straight away and I knew that.
"We worked really hard through the first window to make some changes to the squad and we’ll do the same in January and keep building it until we get to the point where we’ve brought success to this football club.”
Regarding those on the fringes, Postecoglou is delighted with the attitude of all his squad with none “showing signs of disenchantment from the point of view of not wanting to contribute”, while understanding “everyone wants to play”.
“If there ever comes a point where people feel this is not the place for them then I’m happy to have that conversation and we will do what’s best for this football club," he said.