Then, while in Paris, Charlton competed in his first event, the 1500 m freestyle. He won both his heat and his semi-final, qualifying for the final, where he lined up against Borg and Beaurepaire. In the final, Borg immediately claimed the lead and maintained it until the 300 m mark, when Charlton moved alongside him. Charlton forged ahead to lead by 5 metres at the 600 m, before proceeding to defeat Borg by 40 m, while lapping the remainder of the field to win gold in a new world record time of 20m 6.6s. In the 400 m freestyle, Charlton again lined up against Borg and Johnny Weissmuller of the United States. Charlton progressed to the final, finishing second to Weissmuller in both his heat and semi-final. In the final, Charlton, the distance specialist, trailed far behind as Borg and Weissmuller contested the lead. Charlton was eight metres behind at the 150 m mark, before making his move. However, he left it too late and finished a metre behind the leaders, finishing with the bronze medal. Charlton then combined with Ernest Henry, Moss Christie and Beaurepaire to claim silver in the 4 × 200 m freestyle relay behind the United States. Although Charlton had claimed the lead from the Americans in the second leg, the two following Australians were overwhelmed, losing by nine seconds, with the Americans setting another world record.