[3] Joseph Lagrosillière was a candidate for the legislative elections in the northern constituency in 1902, but because of the eruption of Mount Pelée on 8 May, the second round scheduled for 11 May did not take place.

A fierce supporter of assimilation, Lagrosillière, together with the Guadeloupean deputy Achille René-Boisneuf, presented a bill to reform the Constitution of Guadeloupe, Martinique and Réunion in 1914, which would have transformed the colonies into departments of France.

[6] In 1919, he made a political alliance with Fernand Clerc, leader of the progressive factory owners, at the "Banquet de Sainte-Marie" for the following legislative elections against his opponent Sévère, who was allied with the conservative Békés.

[9] Joseph Lagrosillière was arrested in 1931 for "trafic d'influence" (a type of corruption) and imprisoned in Le Havre, France.

[1] Despite his legal troubles, he was re-elected as a deputy in the South of Martinique in 1932, during this term, he established the "Fédération des indigènes d'outre-mer"; Paulette Nardal was his parliamentary assistant and press officer.

Joseph Lagrosillière fought his last political battle in the 1945 municipal elections in Fort-de-France, where he was beaten by more than 5000 votes by the young communist candidate, Aimé Césaire.