She was born in Santander on April 15, 1869. At a very young age she married Ramón de la Serna and moved to Chile where she started to write in the local newspapers; self-taught by need, I learned from life more than from books. The couple came back to Spain in 1898 and ten years later she separated from her husband and moved to Madrid.

Her journalistic collaborations in Spain and America and the success of her novels allowed her to make a living from her writing. She received the most prestigious awards from the Spanish Royal Academy: Fastenrath Prize (1914) for La esfinge maragata (English translation, Mariflor, 1924), Espinosa y Cortina Prize (1916) for El Jayón (the Foundling), Castillo de Chirel Prize (1924) for Tierras del Aquilón (Lands of the North Wind), National Literature Prize (1927) for Altar Mayor (High Altar) and Cervantes Prize for Novels (1949) for Un valle en el mar (A Valley in the Sea). She was one of the first to denounce the harsh social conditions in Spain as it happens in her novel, El metal de los muertos (The Metal of the Dead).

In 1929, the King Alfonso XIII sent her as an extraordinary ambassador to Cuba, Puerto Rico and Santo Domingo and was invited professor in the United States. In 1935 she represented the Government of the II Republic in the celebrations of the IV centennary of the foundation of Lima, where she received The Cross of the Order of the Sun, the highest award in Peru.

She was nominated for the Nobel Prize in Literature by twenty-five nominators from Spain, United States, France, Chile, Colombia, Czechoslovakia, Italy and Sweden in nine editions between 1926 and 1954.

The last fifteen years of her life she was blind, but she continued writing helped by a ruled guideline. After having corrected the second edition of her Complete Works she died in Madrid on May 19, 1955, at the age of 86.