Being a Canadian from Toronto, Oliver Cleary ended up gravitating towards hockey at a very young age. On skates by two years old and in hockey camps within a couple years after that, Cleary started playing organized hockey at a very young age. In a time where kids are completely focused on one sport, Cleary was a multi sport athlete and would leave hockey in the winter. Cleary does credit playing other sports as a skill builder for hockey. He credits baseball for his hand-eye coordination and soccer for his speed. Once Cleary hit around the age of 10 though, he began pulling away from his peers and started showing potential for a future career. His work in the defensive zone was improving a ton and for the most part it felt like he was playing keep away at all times. This is when he began focusing fully on hockey, knowing he didn't have the natural talent in order to carry him.