Born in Saint-Roch-de-l'Achigan, Quebec, Thibault has worked for a variety of different organizations in the government of Quebec, including the Department of Education, the Occupational Health and Safety Commission, and the Quebec Bureau for Handicapped Persons.
She became Quebec's first female lieutenant governor, and the first handicapped lieutenant governor in Canada. Thibault was permanently disabled in a tobogganing accident as a teenager, and uses a wheelchair.