Early career O'Neill spent 14 years of petitioning the jockey board in Australia to allow female jockeys to compete against men, during which time she wrote more than 140 letters to racing administrators in Queensland. On 29 February 1974, O'Neill rode Rene's Magic to victory in the Scarlet Stakes at
Gosford. On 31 August 1974, O'Neill rode Ropely Lad to victory at Eagle Farm in the International Race for Women Riders. On 29 March 1975, O'Neill rode Burgundy to victory in a special race for women jockeys called the Gina Lollobrigida Sprint which was held by the Rockhampton Jockey Club in honour of visiting Hollywood actress
Gina Lollobrigida.
Professional career Prior to O'Neill becoming the first registered licensed jockey in Australia, New Zealand jockey
Linda Jones claimed the honour of being the first jockey in Australia to compete against male jockeys after she was granted an allowance. After her licence was upgraded to allow her to compete in Brisbane metropolitan race meetings, O'Neill became the first Australian women to win a metropolitan race against male riders, riding Samei Boy to victory in the $10,000 Booroolong Handicap at Doomben on 23 June 1979. However, four days after her win in the Booroolong Handicap, O'Neill was suspended for two weeks for careless riding after stewards alleged she had caused interference to two horses in a race at
Bundamba by allowing her horse to crowd two others. In January 1980, O'Neill beat
Roy Higgins in the Unisex Handicap at Moonee Valley. O'Neill lists becoming the first woman to win the Rockhampton Cup at
Callaghan Park on her horse Supersnack in 1990 as a career highlight. In 1997, she was appointed as the secretary of the Queensland Jockeys Association and in 2001, she became a director of the Australian Jockeys Association. ==Honours==