[2][3] He was heavily involved in several rebellions condemning the monarchy and disseminating materials via pamphlets and newspaper in support of the Portuguese Republican Party.

[4][5] He was among the leaders of the 5 October 1910 revolution and the Lisbon Regicide, and later served as Ambassador to Paris, and twice as interim prime minister of the Portuguese First Republic.

[9] His first publication was in O Primeiro de Janeiro in Porto; he later moved back to Lisbon to collaborate with Temps, Correio da Manhã, and O Diá.

[4][10][8] At the end of the 19th century, Chagas founded La Marseillaise (1896—1898), O Berro (1896), Branco e Negro (1896—1898), A Paródia (1900—1907), and A República Portuguesa,[8][6] and became director of Brazilian newspaper O Paiz (1898) and the Portuguese publications A Lanterna (1899) and Batalha (1900).

[6] All of the newspapers he founded, directed, and contributed to were anti-monarchy propaganda tools; his articles were extremely controversial and led to him being arrested several times.

[10] He lived in Porto, Brazil, and Madrid for varying lengths of time before being arrested again in 1896, and again in 1908 for his involvement in the Lisbon Regicide.

[2] During the Republic's early days, Chagas met with Sir Lancelot Carnegie of Britain, Portuguese War Minister Freire de Andrade, and French diplomat Émile Daeschner to keep himself informed.

[10] He withdrew from politics during his recovery and turned down the presidential nomination, preferring instead to continue working as an ambassador in Paris.

[5] He was also a translator; works included prose from Jacques Offenbach's operetta Os Bandidos and Adolphe d'Ennery's play Martyr.