Sonia Denoncourt was born in Sherbrooke, Quebec, Canada. She graduated from the Université de Sherbrooke with a degree in physical education and later attained a master's degree in Sports Administration from the University of Ottawa.
Denoncourt began refereeing in 1978 at the age of just 14 and later decided to give up playing the game to further her career as a referee at the age of 22. Denoncourt became the first female FIFA accredited referee in 1994. She went on the FIFA international list from 1994-2004 and for 11 very active years she was selected to officiate over 100 International matches including men’s professional games in North America, Brazil, Salvador, etc.
She is the first woman in the World to referee the first ever women's football match in the 1996 Olympic Games in Atlanta USA as well as the 2000 Olympic Games in Sydney Australia, deserving the honor of refereeing both the opening and finals games.
She was selected to referee at 3 World Cups 1995, 1999 and 2003 and made her mark to be known as the best women referee in the World for years.
In February 1997, Denoncourt became the first female to referee a professional 1st division men's match in Brazil, when she officiated the opening Campeonato Paulista fixture between São José Esporte Clube and defending champions Sociedade Esportiva Palmeiras.
Among the honors received, she was inducted into the Canadian Soccer Hall of Fame in 2005. Became the First women ever to be inducted to the CSA Life Membership Award in 2015. Inducted in the Quebec soccer Hall of Fame 2004. Inducted in the Hall of Fame for Sherbrooke City 2015. Named Ambassador of the University of Sherbrooke for extended international career and accomplishments. Inducted in the Soccer Club “Les verts de Sherbrooke”. CAAWS award (Canadian Association for the Advancement Women in Sports and Physical Activity) as an international leader in women in sports. Also, named Quebec Soccer Federation's Referee of the Year (5): 1993, 1996, 1997, 1998, 1999. Awarded CSA National Ray Morgan Award for excellence in life time refereeing achievement in 1995. Acknowledge to be the best woman FIFA referee for a decade (1994-2004).
She announced her retirement as a referee on 6 July 2004. In October 2005, Denoncourt was appointed by FIFA as its head of women's referee /senior manager refereeing. Then became the Director of Refereeing at Concacaf in 2014. Currently the Director of Referee Academy for North America at You Are The Ref International.