The inner-city light welter was edged out by European Junior champion Callum Walsh at the Irish Under-18s last year, a decision he disagreed strongly with, and a subsequent broken hand further stunted his progress.
However, O’Leary has stayed strong and kept building – and the past month has seen him make a major statement of intent.
The 18-year-old scored three impressive wins on the bounce against older internationally-experienced opposition to claim the Irish Under-22 title. Following wins over Shane Flavin and Michael Avetisian, O’Leary defeated Matthew McCole on Friday in the decider in front of a massive Dublin crowd.
Looking back on the final, the younger cousin of pro Bernard Roe told Irish-Boxing.com that “I found my distance, I found my timing, I was very good in places tonight.”
“I knew he was going to be awkward, he’s long and skinny and very rangy. I knew I had to get in with a high guard and work. I knew I could outwork him.”
O’Leary will likely head to the European Under-22 Championships in Russia in March but h will also make an early assault on the new 63kg light welterweight division in next month’s Irish Elite Seniors.
It’s the culmination of a lot of hard work from the Dublin Docklands teen in the face of repeated disappointments.
Missing out on the European Youths stung, but O’Leary is now operating at a far higher level.
He recalled how “I thought I got that [v Walsh] – I was happy enough with the performance I put in – I thought I got it and so did everyone else in the Stadium but that’s the way boxing is.”
“I’ve come back stronger from last year – with the breaks in the hand as well. I had a broken hand but I never stepped out, I was still doing work, getting my sprints in, doing my cardio, even when I had a cast on.”
Essentially a full-time fighter, O’Leary is well-known in Dublin circles and has been around the gyms sparring with some top pros.
It’s all part of the process for ‘Big Bang’ who hopes to have an edge when he steps into the international realm.
O’Leary explained how “I’ve been getting good rounds with Davey Oliver Joyce and Gary Cully.”
“The sparring with Gary helped me because he’s similar to the guy who was in the ring with me tonight. I learn a lot from him, we learn together. Him being so big and awkward, when you get out to Eastern Europe to fight the Russians and the Kazakhs, they’re all like that, they’re all difficult.”
Aside from his exciting pro style, what was especially notable about O’Leary’s fight was the large amount of people that were in attendance.
There is a buzz about the youngster and top middleweight Luke Keeler was one of thos in attendance.
Rather than added pressure, O’Leary notes how the support drives him on after what could be described as a dark 2018.
“It gives me a boost, knowing I have so much support,” he admits.
“I’ve a great support structure, they’re all amazing and they know the work I put in.”
“2018 was nothing but failure but I worked hard and getting in the ring today, having the hand raised, and looking it was amazing, seeing all the people there.”