Filiberto Ferrero was born in Biella in 1500, the son of Goffredo Ferrero, marquis of Bordolano, and his second wife Margherita Sanseverino, marqchioness of Bordolano. He was the nephew of Cardinals Gianstefano Ferrero and Bonifacio Ferrero. His younger brother, Pier Francesco Ferrero, also later became a cardinal, as did his nephew, Guido Luca Ferrero.
On May 17, 1518, he was elected Bishop of Ivrea, serving as administrator until he reached the canonical age of 27. He occupied the see until his death. From 1528, he served as the almoner of Francis I of France. In 1530, he served as the ambassador of Charles III, Duke of Savoy to the Republic of Venice. On November 12, 1532, Pope Clement VII named him nuncio to the Duke of Savoy. He was consecrated as a bishop in Rome by his uncle Cardinal Bonifacio Ferrero on December 28, 1533. From April 26, 1537 until March 11, 1541, he was nuncio to Francis I of France.