O’Neill said walking away would have been a mistake, adding his drive to lead the club returned almost immediately.
Speaking after a 1‑0 home loss to Rangers, the veteran manager noted he would review his future and reflect on the situation.
He admitted the break gave him time to think and the decision came quickly, honestly.
Disappointed by the week’s result, he stressed the season is long and he chose to stay as long as the club wants him.
Leaving now would have been poor; without the break he might never have voiced his intent.
Even after three straight defeats, Celtic still sit two points ahead of Rangers at the summit.
The main aim, he said, is to reclaim the league title – a goal that still fuels him after last year’s 23‑game spell.
We have a full campaign ahead and, surprisingly, we remain top of the table at this moment.
He believes the squad can achieve the championship and urges focus on that target.
O’Neill revealed that Jota, back from an 18‑month ACL layoff, could be match‑ready after weeks of training and a friendly against Falkirk.
Chelsea left‑back Landon Emenalo, loaned to Celtic, is expected to join the squad soon once his injury clears, O’Neill added.
Rift between club and supporters ‘really sad’
In my view, the board’s handling of the Green Brigade boycott risks alienating the heart of the club’s support.
The ultras condemned what they called “naked contempt” from the board after the Green Brigade was linked to a protest at the Alfred Dunhill Links Championship.
They claimed a “dark cloud” hangs over the club under Dermot Desmond’s influence, making the environment unsustainable.
The statement called the board’s latest comment an irrational attack driven by Desmond’s agenda.
It accused the board of unfairly tying the group to actions they didn’t commit, while praising those who did.
They described the board’s attitude as sheer disdain, warning of further bans for any manufactured incidents.
The group said meaningful change will require sacrifice, outlining their boycott plan.
They announced they will skip remaining Europa League home games and all Scottish Cup ties, reviewing the stance later.
Former striker Chris Sutton labelled Celtic a “cesspit” in recent comments.
O’Neill, who steered the Hoops to a double last season, said the situation feels familiar and he disagrees with the St Andrews incident.
He called the boycott a sad development, noting the club endured similar issues last year.
He recalled the unity of 80,000 fans in Seville, saying that spirit defines Celtic for him.
Yet he admitted the current atmosphere is disheartening, though he felt unstoppable when the squad rallied late last season.
He urged the team to win matches to rebuild togetherness.