Mira Leung started skating at age three and began taking lessons two years later. As a young child, she skated at the Kitsilano Figure Skating Club, coached by Christine Goodall. She was eight when she first landed a triple salchow and triple toe loop. Joanne McLeod became her coach in 2001 or 2002. Leung debuted on the ISU Junior Grand Prix series in 2002. Deciding to skip the national novice and junior levels, Leung competed on the senior level at the 2003 Canadian Championships. In the 2004–05 season, Leung made her senior Grand Prix debut, replacing the injured Annie Bellemare at the 2004 Skate Canada International. She won her first national medal, bronze, at the 2005 Canadian Championships. After winning the silver medal behind Joannie Rochette at the 2006 Canadian Championships, Leung was named in Canada's team to the 2006 Winter Olympics and 2006 World Championships. She finished 12th at the Olympics in Turin and then 13th at Worlds. Due to a training dispute, McLeod quit as her coach at the end of the season. Leung found a new coach in Christine McBeth at Minoru Arenas in Richmond, British Columbia. On November 9, 2006, Leung announced that she and McLeod had agreed to resume working together, having been advised to reunite by Canadian skating officials at the 2006 Skate Canada International. Leung won another national silver medal and was sent to the 2007 World Championships. On the day of the Worlds short program, Leung felt pain in her left heel and Canada's team doctor told her she had Achilles tendinitis. She decided to compete and finished 24th at the event. In the 2007–08 season, Leung was 5th at both of her Grand Prix events, Skate America and Trophee Eric Bompard. She changed her short program in late December 2007, a few weeks before the 2008 Canadian Championships in mid-January. After winning her third silver medal, Leung received assignments to the 2008 Four Continents, where she placed 5th, and the 2008 World Championships, where she came in 14th. After McLeod decided to end their collaboration in early October 2008, Leung began working with Jennifer Jiang. She finished 6th at the 2009 Canadian Championships. In 2009, Leung began training at Vancouver's Sunset Skating Club with Sonja Hlynka. She withdrew from the 2010 Canadian Championships after placing 15th of 18 women in the short program. In March 2010, Leung and fellow figure skater, Joannie Rochette, walked down the runway at The Heart Truth fashion show in Toronto.