The Dublin light welterweight has signed a management deal with Mack The Knife Global and leaves the vest behind at the age of 19.
The former Docklands amateur won the Irish U22 title in January and has represented the country internationally as well as claiming a bucket-load of underage honours.
While the Tokyo Olympics are just around the corner, O’Leary has decided to make an early move to the pro game.
Sparring pros for the past couple of years, ‘Big Bang’ has been training with Pete Taylor at the Colosseum Gym in Ballyfermot recently.
Here he is joined by new managerial stablemates Gary Cully, David Oliver Joyce, and Luke Keeler along with a swathe of other prospects.
Younger cousin to former light middleweight prospect Bernard Roe, the popular and powerful O’Leary has been earmarked for pro success for some time now.
MTK Global Professional Development Coordinator Jamie Conlan said: “This is another great signing. Anyone who follows Irish boxing will know what a talent Pierce is and we believe his style is perfectly suited to shining as a professional.
“We look forward to helping Pierce achieve his goals and unsurprisingly given his talent, those goals are pretty clear – to become world champion as quickly as possible.”
“We’re very specific with who we want to sign at MTK Global. We look to bring in the cream of the crop and those with elite talent, and that definitely applies to Pierce.”