Of Metis descent and a member of the Gwich'inFirst Nation, Firth was one of the first indigenous North Americans to represent Canada in the Olympic Games. Firth was the recipient of the Order of Canada, the Queen Elizabeth II Golden Jubilee Medal, and the Queen Elizabeth II Diamond Jubilee Medal. She was also voted Canadian Women's Nordic Skier of the Year six times by Ski Racing Magazine. She was the twin sister of fellow ski team member Sharon Firth. The sisters participated in the Territorial Experimental Ski Training program that introduced cross country skiing to northern Canada. Consequently, the sisters made the first ever Canadian cross-country ski team that competed in the 1972 Winter Olympics in Sapporo. They credit the many important lessons they learned while trapping and hunting in their remote home community to their skiing success. In addition to the four consecutive Winter Olympics, the sisters competed in four World Ski Championships, and were members of the National Cross Country Ski Team for an unprecedented 17 consecutive years. Firth won 29 Gold medals, 10 Silver medals, and 3 Bronze medals at the Canadian National Championship level. Together, the siblings accumulated 79 medals at the national championships, including 48 national titles, figures that no other athlete has come close to reaching. Firth won a total of 42 medals out of the 79 won by both herself and Sharon. In 1972 the Canadian Ski Association awarded Firth the John Semelink Memorial Award for her contributions to skiing in Canada, which was shared with her sister. They became the first indigenous women to be inducted into Canada's Sports Hall of Fame in 2015. Firth had previously received a National Aboriginal Achievement Award in the sports category in 2006. In 2008, Firth was inducted into the Hall of Fame of the Banff Sports.
Shirley Firth Larsson was the daughter of Stephen Firth born November 20, 1922 at the Northwest Territories and Fanny Rose Greenland born January 21, 1922 also in NWT. Following her athletic career, Firth went on to live in France where she raised a family and lectured on the Dene and Inuit cultures. Firth died at her home in Yellowknife, Northwest Territories, on 30 April 2013, at the age of 59. The two sisters were also the subjects of an inspiring CBC Documentary entitled "The Olympians: The Firth Sisters". In honour of Firth's memory, the Canada Post put her and her twin sister Sharon's faces on their stamp. Firth was honoured at Canada's Sports Hall of Fame in Calgary's Olympic Park, by her spouse and daughters.
