Jean-Louis Florentz was born on 19 December 1947 in Asnières, Hauts de Seine, France. While pursuing his university studies in the natural sciences, Arabic literature, and ethnomusicology, he enrolled in the Conservatoire de Paris, sudying with Olivier Messiaen and Pierre Schaeffer, as well as with Antoine Duhamel. In 1978, he was awarded the Lili Boulanger Composition Prize, and then multiple awards from the SACEM and the Institut de France.

He traveled extensively for research, including to the Antilles, Polynesia, and Africa, notably to Kenya, where from 1981 to 1982 he was a guest professor at the Kenyatta University College of Thika-Nairobi. He was an élève-titulaire at the Institut d’Étho-écologie des Communications Animales of the École Pratique des Hautes-Études, where he studied equatorial bird polyphonies, publishing several articles on the topic.

In 1989, Jean-Louis Florentz returned to the advanced study of Semitic languages (in particular Ethiopian languages) at the Institut National des Langues et Civilisations Orientales (now INALCO), as well as at the École des Langues Orientales Anciennes of the Institut Catholique. He traveled several times to Israel and lived in close contact with the Ethiopian Orthodox community of West Jerusalem (Däbrä Gännät Monastery).

In 1985, Florentz was appointed as a professor of ethnomusicological analysis at the Conservatoire National Supérieur de Musique de Lyon. He was a resident at the Villa Médicis in Rome from 1979-1981 and at the Casa Velasquez in Madrid and Palma de Mallorca from 1983-1985. He was a Chevalier des Arts et Lettres and in 1989 was awarded the Grand Prix Musical by the City of Paris for his entire body of work; in 1990 he was awarded the Grand Prix Musical by the Fondation Prince Pierre de Monaco for Asún (formerly Requiem de la Vierge), Opus 7. He also won the SACEM Grand Prix de la Musique Symphonique in 1991.

Florentz was elected to the Académie des Beaux-Arts on 5 April 1995, and served as a composer-in-residence with the Orchestre National de Lyon from 1995-1997 and with the Orchestre National des Pays de Loire from 2000-2002.

After a last research trip in 2002, this one to Saharan Tunisia, Jean-Louis Florentz passed away in Paris on 4 July 2004, leaving a catalogue of some fifteen works.