Shannon Smith took up competitive swimming at the age of eleven and found considerable success at both the national and international levels. She set numerous Canadian records in the lead-up to the 1976 Summer Olympics and was selected to represent her nation in the 400 and 800 metre freestyle events, winning bronze in the former and placing sixth in the latter. The Games were her greatest success, but she continued to compete for the next two years, breaking even more records, but retired from swimming shortly before the 1978 Commonwealth Games, citing a growing boredom with the sport. She took up cycling and rowing, but never reached the same levels of competition that she had in swimming. She was made a member of the British Columbia Sports Hall of Fame in 1983.