Trained as a nurse, Helena helped found the Center of Health at the Federal University of Alagoas. She was also involved in the student movements against the military dictatorship. She became a member of the left-wing Workers' Party (PT) and a leader of Socialist Democracy, a Trotskyist caucus in the PT.
In 1992, Helena was chosen as deputy mayor of Maceió as part of the PT-PSB coalition government. In 1994, she was elected as a legislative deputy in Alagoas and in 1999 was elected to the Federal Senate. After Luiz Inácio Lula da Silva of the PT won the presidency in 2002, Heloísa became one of the strongest critics of the new government's neoliberal policies. After voting against party's recommendation in the Senate, she was expelled from the PT in December 2003 for alleged breaking party discipline, the seat in the Senate was kept.
Heloísa and many dissident members of the PT founded a new party, the Socialism and Freedom Party (P-SOL) in late 2004. She is also member of the P-SOL's Freedom and Revolution faction. She was the party's candidate for president in the 2006 general elections.