Nicholas Purnell started rowing in high school and made his first national team in 2009, the same year he won gold in the quad sculls at the 2009 Australian Youth Olympic Festival. One year later, the Sydney-sider competed in his first World Championships, winning bronze as part of the men's eight. He also picked up two World Cup medals in 2010, winning silver with the eight and gold with the four.
In 2011 he rowed in the men's four at the World Championships, winning bronze, before returning to compete in the men’s eight at the London 2012 Games. The Australian’s claimed second in their heat before going on to earn themselves a spot in the 2012 Olympic final with a fourth place finish in the repechage. The crew went on to finish sixth in a strong field, 3.12 seconds behind gold medallists Germany.