A fine athlete, the physical development of the former Bangor Grammar School centre has been as fast as his progress as a three-quarter of pace, power and intelligence. Another Academy graduate, he was given his first Ulster chance as a 21-year-old in the 2013/14 season when he was also part of the successful Emerging Ireland panel. Forcing himself into the Ulster midfield in 2015, he was quickly fast-tracked into the Ireland squad and made his international debut in the 2016 Six Nations Championship.
Stuart is one of the top centres in world rugby, and was a part of Ireland's 2023 Six Nations Grand Slam success and the autumn 2023 Rugby World Cup squad.