Luisa Capetillo Perón was born in Arecibo on 28 October 1879. Her father, Luis Capetillo, came from the Basque Province of Spain; he had been influenced by the advanced ideas of citizens' and workers' rights. His mother, Margarita Perón, came to the island from France in the mid-19th century. She was an only child. 

After Luisa's father taught her to read, write and learn the rules of mathematics, Luisa attended the public school of Doña María Sierra Soler. Her academic aptitude earned her awards. This was the kind of education that women of her time received. Luisa had access to French literature, as she learned the language from her mother, and her love of reading made her self-taught.

She was an advocate of free love, the rationalist school, spiritist, vegetarianism and exercise as a way of life. In 1904 she began writing essays. She had three children without being married.

She stood out as a labour leader, feminist, writer; she worked in the needle industry to support her family. 

Later she collaborated with workers' publications, an activity she carried out throughout her life. In 1906 she began working as a reader in tobacco factories in her hometown, where she joined the Federación de Torcedores de Tabaco, a union affiliated with the Federación Libre de Trabajadores de Puerto Rico.

Louise championed women's suffrage and universal suffrage, although her main concern was the organisation of women in trade unions. In 1910 she published her book Humanity in the future.

She also edited a magazine "La mujer", of which no copy has survived. In several of her writings the theme of the defence of women and their rights is prominent. 

She was the first woman in Puerto Rico to wear trousers, which even led to her arrest in Cuba on a trip to the neighbouring island. She herself defended herself against the accusations, as there was no law prohibiting this practice, beyond the culture or machismo of the time. When asked for evidence of the prohibition, she was released when it was not provided. Upon her return to the island, she was a labour leader in agricultural strikes in Patillas, Ceiba and Vieques. 

Capetillo was a believer and advocate of spiritist thought, which she used to express herself and to promote the equality of all human beings on earth. In her books she spoke about the need to educate people in this way, which today makes her a forward thinker for those years. In her books and works she talked a lot about poverty and communities, and even addressed issues such as anarchism. 

She published four books:

• Libertarian Essays (1907)

• Humanity in the future (1910)

• My Opinion on the Rights, Responsibilities and Duties of Woman (first edition, 1911; second edition, 1913) 

• Influences of Modern Ideas (1916)

She died of tuberculosis in Rio Piedras, Puerto Rico, on 10 April 1922, aged 43. In reporting her death, the newspaper "Unión Obrera" of 15 April 1922 read: "Her burial was poor, as they regularly are for the leading apostles of the great causes of humanity".