Irwin first started riding a bike at the age of 3 on a Yamaha PW50 but became professional in 2008 where he competed in Motocross championships achieving multiple wins and successes through to the end of 2014. He moved on to road racing in 2016, and competed in the British Superteens Championship where he was runner up by 1 point, achieving 8 race wins and 20 podiums during this season. He also competed in the Irish 125 series and crowned the champion with a 100% win record.

2017 saw Irwin move to the British RRV 450 Aprilia challenge, collecting 6 race wins and gaining 2 lap records at Mondello Park in the Lightweight Supersport Category. The next chapter was a ride in the British Motostar Championship, for the 2018 season where he finished sixth in the championship, with his best achievement being a start of last place (32nd) at Brands Hatch to finish third!

2019 saw a move to race in the British Talent Cup where he had front row starts at the Donington World Superbikes, SilverstoneMotoGP and Czech Republic Grand Prix of Brno MotoGP rounds, finishing in a podium position at the latter. He finished fifth in the British Talent Cup series whilst back home, he became the youngest ever Supersport 600 race winner in the Irish Championship.

He then turned his attentions to the Pirelli National Superstock 600 championship in 2020, where he was crowned the top rookie in the championship, with 3 race wins, 4 podiums and 3 pole positions. His final achievement of this season was winning the Young Irish Motorcyclist of the Year award, a great recognition of all his racing efforts over the years.

In 2021 he ventured into the British Supersport series where he remained until his championship win in 2025. In his rookie year, he finished ninth in the Championship and continued the success in 2022 being the only next generation supersport bike to finish on the podium in British Supersport, along with multiple front row starts.

Continuing in the supersport class, 2023 saw Rhys achieve countless race wins and podiums that lead to an opportunity to wildcard in the World Supersport race at Donington Park where he finished in the points. 2024 proved to be a challenging start, however he teamed up with the Gearlink Kawasaki team at round 4 where he finish ninth in the championship despite only competing in part of the season.

But 2025 became the ultimate year of racing achievement for Irwin where he won the Quattro Group British Supersport series and was crowned champion after coming out on top in a season-long battle with three former champions. He also won the Short Circuit Rider of the Year award at the Irish Motorbike Awards which took place in January 2026, and now he steps up to the British Superbike Championship with Hawk Racing.