During the 2008 Oceania Swimming Championships held in Christchurch, New Zealand, Napoleon won gold in the 4 × 200 m relay and bronze in the 200m butterfly.

At the 2011 Australian Swimming Championships, he won the 400m freestyle in a time of 3:45.16, making him the 4th fastest Australian 1500m swimmer of all time, behind Olympic Champions Ian Thorpe, Grant Hackett and Kieren Perkins In what could be described as an unlucky meet for Napoleon, he finished in 13th place for both the men's 400m and 800m freestyle.

[1] After Napoleon qualified to contest the 400m and 1500m freestyle at the 2010 Commonwealth Games in Delhi, swimming governing body FINA imposed a three-month doping ban on him due to a failed drug test taken in November 2009.

[2] Napoleon appealed the decision made by FINA to the Court of Arbitration of Sport (CAS) resulting in the ban being backdated to 15 June 2010.

Although he had missed out on vital training and preparation, Napoleon was then eligible to compete in Delhi where he claimed silver in the 400m freestyle and gold in the 4 × 200 m relay.