Malavoy first entered politics in 1994 and was elected in the riding of Sherbrooke where she was briefly the Minister of Culture and Communications in the Jacques Parizeau cabinet. She had to step down from her position on November 25, 1994, as it was found that she had illegally voted during the Quebec Referendum in 1980 as well as other federal and provincial elections since she was not a Canadian citizen at the time. After an eight-year retirement from politics, she was elected in Taillon in a by-election, succeeding the former minister Pauline Marois. She was re-elected in the 2007 elections. After being the critic for municipal affairs during the first parliamentary session, she was named the critic for education after reports that Diane Lemieux, who held the portfolio during the spring session, would retire from politics following a disagreement with Marois, who was named the PQ leader in July 2007.