Cline first took part in ski cross races in the late 1990s. She won the Winter X Games in 1999, 2001, 2003 and 2003, while she came second in 2004. She made her debut in the Freestyle World Cup on November 30, 2002. In the first ski cross World Cup race in history, she finished second behind Magdalena Iljans . She celebrated her first World Cup victory on January 11, 2004 in Pozza di Fassa , the second six weeks later in Naeba . There were also two more podium places.
At the end of the 2003/04 season, Cline resigned from elite sport and became the mother of two children. After ski cross had been declared an Olympic discipline, she attempted a comeback at the end of 2008 and was able to establish herself again at the top of the world at the age of 38. In February 2009 she achieved her third World Cup victory in Cypress Mountain . At the beginning of the 2009/10 season, Cline did not quite reach the level of the pre-winter season and missed qualification for the Olympic Games due to strong competition within the team. In March 2010, she achieved another World Cup podium finish. After winning the Canadian Championships that month, she resigned for good.