The surprise is that he is doing so now, without Celtic.
St Johnstone's 23-year-old midfielder is eight days away from his biggest footballing occasion, a match being hosted by the club which dealt him his greatest disappointment. O'Halloran was on Celtic's books as a teenager, a contemporary of James Forrest and Gregg Wylde, who played youth football there before being released and signing for Rangers. O'Halloran emulated Wylde rather than Forrest by also being released, in 2007.
He moved to Bolton Wanderers before loans at Sheffield United, Carlisle United and Tranmere Rovers and then, in January, a permanent move back to Scotland with St Johnstone.
When he rolls up at Parkhead for the Scottish Cup final against Dundee United a week tomorrow he will have a busload of family and friends in tow from Moodiesburn, his home town. "Everyone is asking me for tickets even when they haven't seen me play before," he laughed.
O'Halloran has played 17 times for St Johnstone since arriving on an 18-month contract. In the 3-3 midweek draw with Celtic his runs and dribbling troubled the champions, while he scored a late equaliser with a header. It was a timely display given that manager Tommy Wright has only one more game, against Inverness Caledonian Thistle on Sunday, to assess his players' form ahead of the cup final.
"The manager told us that we were playing for places," said O'Halloran. "I wouldn't like to be the manager, having to pick the team now. I hope I've made my mark and will play in the final.
"It would be a dream come true to play at Celtic Park in a final. I reckon we've got a great chance. We're looking forward to it."