Cabral began his political career within the student movement at UFMT. He was also the director of the Doctor's Union (Sindimed).
He was elected to his first term as a councilman in Cuiabá in 2004, and was later reelected in 2008, a position he held until December 2012. In 2012, he ran to become the mayor of Cuiabá,[2] advancing to the second round and receiving 140,798 votes. However, he finished in second behind eventual winner Mauro Mendes.
During the 2014 Mato Grosso gubernatorial election, the PT selected him to run as their gubernatorial candidate in Mato Grosso.[3] His vice-gubernatorial pick was Tetê Bezerra.[4] He once again came in second place, with 472,507 votes, with Pedro Taques being elected.[5]
In 2018, he ran to become a state deputy and was elected.[6] He began his term with the Legislative Assembly of Mato Grosso on 1 February 2019. He was reelected in 2022 with 47,533 votes, being the most voted for candidate in Cuiabá.[7]
In 2024, he ran again to become the mayor of Cuiabá. After voting commenced on 6 October 2024, he advanced to the second round against Abilio Brunini of the Liberal Party (PL).[8] He was defeated in the second round.[9]