As a devoted Celtic supporter with strong family connections to the club, it is perhaps fitting that such a privilege was enjoyed in silence.
The 23-year-old is no longer lost in the innocent ambition of his schooldays, though.
He is, finally, about to fulfil the dream of taking centre stage in a showpiece fixture at his chosen place of footballing worship.
The fact he will be doing it in a royal blue shirt is neither here nor there. What O'Halloran wants most of all is to hear the noise, to hear that concrete bowl he once regarded with such awe come alive in her own special way and leave his ears ringing until well into Sunday morning.
The St Johnstone midfielder came through the ranks at the SPFL Premiership champions' youth academy, where his father Michael still coaches, and where they were treated towards the end of each season with a kickabout inside Celtic Park, until he was released to rebuild his career at Bolton aged 16.
Naturally, no-one other than the cluster of mums and dads in the Main Stand paid the slightest bit of attention. Tomorrow, a few more will stop to watch O'Halloran and his current side take on Dundee United in the William Hill Scottish Cup final and he believes there is no better venue in which to win the kind of glory that stirs the blood no matter your age.
"I'm happy the game is at Celtic Park because it generates a great atmosphere, especially in the big games," said O'Halloran.
"At Hampden, the fans are maybe a bit too far away from the pitch, but they are right on top of you at Celtic Park. When you are a young player going through the system at Celtic, they give you a wee run-out on the pitch at the end of the season.
"I don't think there were any fans there when I played. It was just parents and what-not. The place would be completely empty and there would be no atmosphere whatsoever. Of course, it still meant a lot to you as a young kid.
"The first time I played there properly was with St Johnstone. We were 3-0 down when I came on earlier in the season and it was still good to play in such a big stadium, but it will be much better this weekend. It is amazing the number of fans that are making the trip through and we want to go and win the cup for them as well as ourselves to give them a good day out.
"Would we be legends? I don't know about that, but it would be great if we did it."
It is a day they have waited for all their lives. The Perth side are making their first appearance in a Scottish Cup final and so much of the talk this week has been about them winning the first major trophy of their 130-year existence.
O'Halloran remains calm under the weight of expectation. When you have breathed in the high-octane atmosphere of English football's end-of-season play-offs and taken a penalty kick in one of the most remarkable shoot-outs seen on these isles, you have earned to the right to approach the most important match of your life with an ever-so-slightly nonchalant air.
O'Halloran was on loan at Sheffield United two years ago when they made it to the League One play-off final with Huddersfield Town. After coming on in extra-time with the scoreline goalless, he scored the 18th penalty in sudden-death to make it 6-6 - only for his side to eventually lose 8-7.
"Wembley is one of the best stadiums in the world," he said. "The game went to penalties and I hit one, which was a good experience of handling pressure. This is a national cup final, though, and it will be the biggest game of my career so far. I'm looking forward to it. It's exciting, but we'll handle the occasion. I'm confident in my ability and what I can do on the day.
"There might be a few butterflies on the day, but we will all be fine. We have a good record against Dundee United, having beaten them three times this season, and that gives us a bit of confidence."
O'Halloran, who arrived at McDiarmid Park on an 18-month contract in January, believes the Perth side's semi-final victory over Aberdeen at Ibrox should serve as a warning against complacency.
St Johnstone had continually failed to hit the net against Derek McInnes's side before that match, barely laying a glove on them all season, but two goals from Stevie May made the difference when it mattered most.
"Aberdeen had beaten us and we hadn't scored a single goal against them, but it was brilliant the way we managed to come back after being 1-0 down," recalled O'Halloran.
"That was one of the best days I've had in football. Beating Aberdeen is a warning for us, though, because it proves a winning run will always come to an end.
"United have beaten us 4-0 already this season. Their front line is dangerous. Stuart Armstrong, Gary Mackay-Steven and Nadir Ciftci have all been very good this season."