He lived for two years in France during his childhood, also playing rugby, and speaks fluent French.

Despite playing in several strong school teams with fellow future professional rugby players such as Dan Leavy, James Ryan and others, he did not win a Leinster Schools Rugby Senior Cup medal.

He debuted for the team at the 2019 London Sevens,[4] and also played in a 2019 European qualifying tournament for the 2020 Summer Olympics.

[5] Kelly was a member of the Ireland national rugby sevens team that qualified for the 2020 Summer Olympics.

[9] Kelly earned a Law degree at Trinity College and began working as a trainee solicitor at McCann FitzGerald LLP in 2022.