The son of Gerolamo De Ferrari and Isabella Adorno, he was born in Genoa on July 20, 1732, and was baptized in the basilica of Santa Maria delle Vigne.

Ascribed to the Golden Book of Genoese nobility on December 6, 1754, along with his brother Baldassarre, for the next twenty years he apparently never held public office for the Republic of Genoa.

It was only in 1774 that Raffaele Agostino De Ferrari's name appears among the members of the Senate, and several times he was senator until his dogal appointment, father of the Commune in 1776, attaché to the Junta di Marina and to the Borders in 1780, syndicator of the Civil Wheel in 1783 (he then had to resign in 1784 because of a case concerning him that was to be heard in that court), protector of the Bank of Saint George in 1786.

During his mandate there was the fortunate capture, on 11 August 1788, in the waters in front of the town of Bordighera, of an Algerian Xebec, of the 117 Turkish sailors taken prisoner by the Genoese galleys San Giorgio and Raggio, 50 were killed.

Arrested and closely guarded he remained imprisoned with 11 other members of the Genoese nobility believed to be "always enemies of the present system and fond of its former government."