A member of the Socialism and Liberty Party (PSOL), she was initially a candidate for President of Brazil in the 2018 Brazilian general election, before being chosen as the vice presidential running mate of nominee Guilherme Boulos.

At the age of 15, she left home at the invitation of FUNAI and moved to Minas Gerais, where she completed her initial education at an agricultural boarding school.

[2] As an activist, she has been at odds with the ruralistas in the National Congress, a group of conservative legislators allied with agribusiness interests who favor further development on public lands.

In 2011, Guajajara left the party due to its alliance with Roseana Sarney, a conservative politician who served as Governor of her home state of Maranhão.

Despite her misgivings, Guajajara denounced the impeachment of Dilma Rousseff that led to the installation of Michel Temer as President, describing it as a "coup".

[18] In the end, she was chosen by labor leader Guilherme Boulos to serve as his vice presidential running mate on the PSOL ticket.

[21] In January 2023, President Luiz Inácio Lula da Silva appointed Guajajara to lead the Ministry of Indigenous Peoples.