As he limbers up for his 22nd game of the year in which he hopes to claim a 21st win and a second Leinster senior club title, it was a difficult decision he took at the start of the year that set him on his way to glory.
“I’ve taken a step back from UCD completely,” he said in January about his call not to play college football or hurling.
“I had to prioritise what I was going to do and I couldn’t have committed to the U21s as well so I decided Cuala would be my focus and, to be honest, Jim Gavin agreed with me and so did (Dublin U21 football manager) Dessie Farrell that it’s not often you get these opportunities with the club so you’ve got to take it with both hands.”
That the now 21-year-old surely did — claiming provincial and All-Ireland honours with both.
There may be a “what if” for Irish Examiner columnist John Divilly, who had hoped to lead UCD to a second successive Sigerson Cup title only to be foiled by St Mary’s in the final, but he couldn’t criticise O’Callaghan, not then and not now as he has proven to be correct in his stance.
“He’s top class,” says Divilly, who also coached him and older brother Cian in The Harold Primary School in Glasthule during his teaching years there.
“Nothing seems to faze him. He’s what you would expect – dedicated and hard-working.
“He would always have been practising away from training and I rarely saw Cian or himself without a hurley or a ball in their hands.
“Both of them stood out just because of their enthusiasm firstly and then their talent. There were always buzzing around the pitch, so eager to learn the game. They were very easy to coach and that hasn’t changed since.
“There’s no airs or graces about any in the family. Con’s very much like Jack (McCaffrey) in that way — just because he has won something isn’t going to change him in any way. He’s popular too — all the UCD guys like him.”
Paul Flynn can only speak glowingly of his young Dublin team-mate too.
“That guy is mature beyond his years. He’s just so level-headed. He never lets any of it get to him.
“If he won a game or lost a game, I don’t think you’d see too much of a shift in his emotions.
“He loves playing Gaelic football and hurling. You can see it in every aspect that he does. He loves training. He loves the grind of putting in a big shift. He loves it all. But at the same time, I see a level-headedness to him.
“He was in Grant-Thornton there doing an internship with his third year in college and he’s engaged in it. And I’m just thinking… I’d say whatever that guy puts his hand to, he’s going to be good at it.
“But the reason he is so good is because he’s very talented but more so, because of his attitude. His mindset about things. He’s got a really great way about him. And he’s going to be a superstar for years.”
Along with former Armagh footballer Des Macken, Divilly assisted Con and Cian’s father Maurice, the Westmeath-born solicitor who lined out for Dublin footballers in 1983, when he was in charge of a southside U14 development football side.
Con’s mother Rionach was a star hockey player. Con’s cousins John and Colum Sheanon also feature on the Cuala senior hurling team. There is plenty of pedigree in the clan.
That alone, obviously, isn’t enough as the player himself would testify. When O’Callaghan returned to the Cuala hurling panel after landing his first All-Ireland SFC title with Dublin last year, his team-mates couldn’t get over how conditioned he was. O’Callaghan had always been naturally strong but his work with strength and conditioning coach Bryan Cullen had seen him develop even more.
“I’ll tell you a little story,” smiles Flynn. “It was probably his first or second training session up in Inisfails. I had just seen him playing underage. I didn’t know a hell of a lot about him. But I definitely didn’t think he was a hardy boyo.
“We were doing a tackle box. You know that drill, every club does it? Well, we do it too. And I was in it with him. Anyway, he hit me a dunt and I was winded for about 30 minutes. I couldn’t train… I was running around training pretending I wasn’t hurt.
“He’s as hard as nails and he has been since the start. He has that inner strength. Not just the strength you get from doing weights.”
The country knows all about that now. Capping an almost perfect year is almost upon him.