After narrowly missing a bronze medal at the 1991 World Championships in the 200-metre individual medley, Overton went on to a 5th-place finish at the 1992 Summer Olympics in Barcelona, Spain.

She won the bronze medal in the 200-metre individual medley at the inaugural 1993 FINA Short Course World Championships in Palma de Mallorca, Spain, followed by the gold medal two years later at the 1995 FINA Short Course World Championships in Rio de Janeiro.

After winning a bronze medal at the 1994 World Championships, she moved from Sydney to Brisbane to train with Susan O'Neill and Samantha Riley under coach Scott Volkers.

Overton retired from swimming after graduating with high honors from the Haas School of Business and finishing 11th at the 2000 Summer Olympics in Sydney.

She attended St Ives High School in Sydney, where she still holds many swimming carnival records.