A member of the Left Bloc (Bloco de Esquerda), she has been a deputy in the Portuguese Assembly of the Republic since 2015, representing Setúbal.

Joana Mortágua has a degree in international relations with a specialization in Latin America, from the Instituto Superior de Ciências Sociais e Políticas (ISCSP) (Institute of Social and Political Sciences) of the University of Lisbon.

[2] Mortágua's political involvement began at the age of 15 when she volunteered for the Associação Justiça e Paz (Association for Justice and Peace), based in Coimbra, an organization that defends human and women's rights.

Later, she was active in various student movements, including the fight against the Bologna Process, a European initiative to ensure comparability in the standards and quality of higher-education qualifications.

The elections in 2022 were called early by the prime minister, António Costa, following the failure of the Left Bloc and the Portuguese Communist Party to support his budget.