She worked at the national secretariat, the Centre des services sociaux de Montréal and the Social Development Council of Metropolitan Montreal as a staff member.

In 1984, she was appointed Minister of Cultural Communities and Immigration by Quebec Premier René Lévesque, and served until the government's electoral defeat in the 1985 election.

In 2002, she became the first woman to serve as Speaker of the National Assembly, and remained in that capacity until the 2003 election, after which she joined the PQ on the opposition benches.

She was re-elected in the 2007 elections and named the PQ critic in social services and later she was also giving the portfolio of Status of Women.

In early July 2013, Harel allied Vision Montreal with mayoral hopeful Marcel Côté.

After her own district was abolished, Harel ran for councillor in Sainte-Marie, the eastern section of Ville-Marie, but lost to Projet Montreal's Valérie Plante.

[7] In January 2014 Harel announced her intention to revive Vision Montreal but not to run for office again herself.