Born in the Royal Palace of Caserta, he was baptized Francisco Javier Antonio Pascual Bernardo Francisco de Paula Juan Nepomuceno Julián of Naples and Sicily.

His father was Charles VII, King of Naples and of Sicily since 1735.

His mother was Maria Amalia of Saxony, daughter of Augustus III of Poland.

In 1759, on the death of his uncle King Ferdinand VI of Spain without children, his parents, his brothers Charles and Gabriel, and his sisters, Maria Luisa and Maria Josefa left for Spain where her father was crowned King Charles III of Spain.

He grew up at the Royal Palace of Aranjuez, but died of smallpox on 10 April 1771 at the age of 14.