[2] At the time of the French invasions of Portugal, Clemente enlisted in the Academic Battalion that was organized in the country and which was commanded by José Bonifácio de Andrada e Silva.

[4] Unknown in Brazil, he was forced to work as a lawyer for a living, and so he remained until 1819, when he was nomitated juiz de fora and tasked with founding the village of Praia Grande (present-day Niterói).

José Clemente Pereira led the popular demonstrations of the so-called Dia do Fico, when then prince regent Pedro was convinced to disobey orders from the Portuguese cortes to leave Brazil.

At this time he was elected president of the Municipal Chamber of Rio de Janeiro, from which he received, signed by his colleagues, a document in which they expressed admiration and recognition for his opposition to the Portuguese officers on June 5, who, armed in the Largo do Rocio, wanted to swear the Portuguese Constitution and force prince Pedro to obey orders from general Jorge de Avilez.

The freemasons, led by Joaquim Gonçalves Ledo and José Clemente Pereira, moved to dissuade prince Pedro from complying with the orders of the Portuguese cortes, which requested his return to Europe in 1821.

Although initially inclined to respect the directives of the cortes, the prince regent was convinced by Gonçalves Ledo and José Clemente, who managed to get representatives from Rio de Janeiro, Minas Gerais, São Paulo and Bahia to adhere to the request that he not leave Brazil, leading to the Dia do Fico on 9 January 1822.

He held several important public positions during the Reign of the same Emperor who had exiled him: Minister of the Empire, at the same time of Finance, Justice, Foreigners and War.

José Clemente renovated the Post Office and opened the first annual painting exhibition, hosted at the National Academy of Fine Arts.

In Rio de Janeiro, he took measures mainly focused on infrastructure, such as the plumbing of the waters of Lagoinha and Paineiras, the construction of fountains in Laranjeiras, Cosme Velho and São Cristovão, in addition to several improvements in the neighborhoods of Catete and Maracanã.