The son of Benjamín Fontao and Marciana Meza, he was born in Tape Ka'aty, located in the San Pedro Department, Paraguay, on December 29, 1900.
Flores composed the lyrics of the songs "Arribeño Resay", "Ka'aty" and the first version of "India" for him.
He wrote the lyrics of "El Arriero", with Félix Pérez Cardozo composing a song for it later.
When Manuel Ortiz Guerrero heard Flores' interpretation for the guarania (a traditional Guarani folk song) "India" for the first time, he showed admiration for the piece, but questioned the lyrics, saying that they did not have the same transcendence as the song, and offered to compose better lyrics.
Some of his contributions to the Paraguayan folkloric canon include: He also produced theatrical plays and published a poem book.