Willis-Roberts was born in the Melbourne suburb of Preston. She first competed at the 1988 Seoul Paralympics with the Australia women's national goalball team, when it finished seventh. She moved to athletics and at the 1990 World Championships and Games for the Disabled in Assen, Netherlands, she won a bronze medal in the women's shot put B2. At the 1992 Barcelona Paralympics, she won a gold medal in the Women's Shot Put B2 event, for which she received a Medal of the Order of Australia, and a silver medal in the Women's Discus B2 event; she also competed in the national goalball team, which came seventh, and the Women's Javelin B1&gt;3 – event. In 1995, she competed in the World Championships for powerlifting. In the 1996 Atlanta Olympics, she won a silver medal in the F10-11 shot put and also competed in the F10-11 discus throw. In 2000, she won an Australian Sports Medal. That year, she competed in her home country in the 2000 Sydney Paralympics where she won a gold medal in the F12 shot put and a bronze in the discus throw. At the 2004 Athens Games, she won a bronze medal in the Women's Shot Put F12 event and competed in the Women's Discus F13 – event. She also competed in the 2008 Beijing Olympics where she won a bronze medal in the women's F12-13 shot put event. After the Beijing Games, she had a shoulder reconstruction and tore her left hamstring off the bone at a training camp. In 2011, she was part of the Australian national goalball team that finished sixth at the IBSA Goalball World Cup.