At the age of 17 Alexandre Dupont lost his right leg in a motorcycle accident. About a year later he watched a wheelchair race from the 2004 Paralympics in Athens, Greece, on television. Dupont decided to try the sport. Thanks to his competitive nature and athletic ability, Dupont has found success on the track.
In 2018 at the Commonwealth Games, he won the gold medal in the men's 1500m upsetting local favorite Kurt Fearnley. In 2016, he helped Canada to the bronze medal in the 4X400-m relay. In 2015, he was a triple gold medallist at the Toronto Parapan American Games with victories in the 400m, 800m and 1500m.
He has competed at the last three IPC World Championships helping Canada to gold in the 4X400m relay in 2013 and bronze in the same event in 2011. He also took third spot at the 2014 Commonwealth Games in the 1500m. He competed in four events at the 2012 Paralympics in London.