Llorens Torres was born in Juana Diaz, Puerto Rico, his parents, Luis Aurelio del Carmen Llorens and Marcelina Soledad de Torres, were the wealthy owners of a coffee plantation. In Collores (a section of Juana Diaz), Llorens Torres was always in contact with nature, which accounts for the love that he felt for nature and country. Llorens Torres always stated that he was proud to come from "Collores". His Catalan grandfather, Josep de Llorens i Robles, had immigrated from the village of Llorens, which belongs to the town of El Vendrell in Tarragona (Catalonia, Spain).

He went to school in Mayagüez and Maricao. Llorens Torres went to Spain after he finished his secondary studies on the island. He studied at the University of Barcelona and became a lawyer. He then proceeded to study Philosophy and Letters at the University of Granada where he obtained a Doctorate degree in both disciplines. In Spain he published his first book of poetic verses "Al Pie de la Alhambra", which was dedicated to his girlfriend, Carmen Rivero.

He returned to Puerto Rico in 1901, married, and moved to Ponce where he established his own law firm (Nemesio Canales later joined his firm) and collaborated with the newspaper Lienzos del Solar. During this time he wrote some of his best works.

When Llorens Torres returned to Puerto Rico he found a political situation completely different than from the one that he had left. Puerto Rico had been annexed by the United States, thus motivating Llorens Torres to join the political Union Party which defended the ideal of independence for the island. He transmitted his beliefs to the public through his poem "El Patito Feo" (The Ugly Duckling). He became a member of the legislature when he was named to the Camara of Delegates from 1908 to 1910 representing the municipality of Ponce. On February 8, 1912, together with Rosendo Matienzo Cintrón and Manuel Zeno Gandía, he wrote a manisfesto which stated that it was time for Puerto Rico to have its independence. That year Llorens Torres, Rosendo Matienzo Cintrón, Manuel Zeno Gandía, Eugenio Benítez Castaño, and Pedro Franceschi founded the Independence party which was the first party in the history of the island to exclusively want Puerto Rican independence. Eugenio Benítez Castaño was named president of the short lived political party. In 1913, Llorens Torres co-founded with Nemesio Canales La Revista de Las Antillas, a literary publication. Llorens Torres died in Santurce, a sector of San Juan, Puerto Rico. He was a defender of the independence ideal until the day that he died.

The Government of Puerto Rico has honored the memory of Luis Llorens Torres by naming a public housing project in Santurce after him. Among the other things that were named after him are an avenue in San Juan, a high school in Juana Diaz, and a children's academy in New York City. There is a bust of him in front of the high school named after him and there is a statue of Luis Llorens Torres, sculpted by the Puerto Rican sculptor Tomás Batista, in the "Plazita Famosa" of Juana Diaz.