Perhaps only Jock Stein is held in higher esteem than O’Neill by Celtic fans. Younger supporters have now seen a fourth league triumph, to go with the stories of O’Neill’s previous three.
And there will be games within it that go down in folklore, so many of them sealed with late goals.
Wednesday’s controversial late win at Motherwell, after which O’Neill made a point of going to the away end and revving them up before Saturday’s decider against Hearts, which somehow contributed even more drama to an extraordinary tale.
When O’Neill left after his first spell this season, he stated he was taking the tracksuit he had worn on the touchline. A memento of an unexpected chapter. He returned, as did the work clothes, and now he has a trophy to go with it.
The club legend has made no secret of how surreal and how meaningful his unexpected return has been.
On top of that, he has represented a unifying figure amid fan unrest aimed at the boardroom. The atmosphere at Parkhead on the final day was almost unthinkable not long ago.
But is there more to come from O’Neill? He was asked directly about his future after the win over Hearts, but refused to commit.
“I genuinely don’t know,” he stated. “Has anybody talked to me? No, but I wasn’t expecting that. There will be time for conversations after the cup final.
“I’m pretty old so it does take it out of you.”
His record this season shows his still has the Midas touch, but whether he has the appetite to go again is another matter.
“I think he’s done what he can,” former Celtic goalkeeper Pat Bonner stated. “I don’t think he needs to go again. The club needs to go in another direction.
“At 74, Martin O’Neill has hit the pinnacle. He’ll go down in history.”
If he does decide to walk away, his successor has mightily big shoes to fill.