Gregg won a bronze medal in the 500 metres during the 2009 World Short Track Speed Skating Championships, she also won another bronze in the women's 3000 m relay at the same championship. During the 2008 World Short Track Speed Skating Championships she won a silver medal as participant in the women's relay along with fellow speed skaters Kalyna Roberge, and Tania Vicent. She won her first World Championship gold medal in Sofia in 2009. Going into the 2010 Olympics, Gregg was a medal contender in the 500 m and the 3,000 m relay. In the final at the Vancouver Olympics Gregg suffered through numerous first corner falls and restarts both in the quarterfinals and finals. In the final she was pushed out of the way by Arianna Fontana and was out of the race by the end of the first corner. Gregg finished 4th in the 500 m. On February 24, she won a silver medal in the 3,000 metre relay, along with Tania Vicent, Kalyna Roberge and Marianne St-Gelais.