 Rousseau interrupted her teaching career to raise her children.She returned to the workforce in 1952 as a production supervisor in a textile factory and became active in her union becoming a director on the executive committee of Sherbrooke, Quebec's labour council and then vice-president of the Canadian Federation of Textile Workers and vice-president of the Confédération des syndicats nationaux (CSN), one of Quebec's principal trade union federations.She served as a CSN delegate on the Economic Council of Canada, the Royal Commission on the Status of Women and the Third World Conference on Work held in Brussels.