Alex Purnell made his Australian representative debut in 2013 in a junior quad scull which contested the 2013
Junior World Rowing Championships in Trakai to an eleventh place finish. In 2015 he was selected in an U23 quad scull which competed at the
World Rowing U23 Championships in Plovdiv and rowed to a bronze medal. - the fourth Australian men's eight to ever do so. He was back in the Australian quad for the
2018 World Rowing Championships in Plovdiv. That crew placed third in their heat and then in the repechage they went out hard and alongside New Zealand they surprised the Lithuanian world champions knocking them out of the final. In the final the Australian quad rowed through most of the field from the 1000m mark and finished in second place for a silver world championship medal. The eight were looking for a top five finish at the 2019 World Championships to qualify for the
Tokyo Olympics. The eight placed second in their heat and fourth in the final and qualified for
Tokyo 2020. This combination had won the 2021 Australian national title in the coxless four. In Tokyo the Australian coxless four won their heat and progressed straight to the A final where they held a lead from the first 500m, and were being challenged by the British four who lost their steering and control in the final 500m. With Purnell steering straight and true from the bow seat the Australians kept their composure and held off the Romanians in a tight finish, taking the gold in an Olympic best time. They took gold at the
World Rowing Cup II in Poznan in June, won the
Stewards Challenge Cup at the
Henley Royal Regatta in July and a week later finished second at the WRC III in Lucerne. At the
2022 World Rowing Championships at Racize, he rowed in the Australian coxless four to a silver medal. At the
Rowing World Cup II in Varese, Italy they raced as Australia's M4- entrant. They made the A final and won the silver medal behind the Great Britain four. At 2023's RWC III in Lucerne, that unchanged four again raced the M4-. They won their heat and semi but again were beaten into second place by Great Britain in the A final. That crew was selected intact as Australia's coxless four for the
2023 World Rowing Championships in Belgrade Serbia. They placed second in their heat. They placed 3rd in the A/B semi-final at which point they qualified an Australian M4- boat for the
2024 Paris Olympics. In the A final the Australian four finished fifth, giving them a fifth place world ranking from the regatta. ==Accolades==