The authors agree that the surname derives from the medieval name of Germanic origin Fulcus, in its direct form or in its genitive Fulconis. V. Blunda specifies that the Germanic root is folc, employed here in its simple form, without a second compositional element.

E. Rossoni documents the medieval use of the name with several testimonies: in 1098, a charter of Count Rogerius of Calabria and Sicily mentions Fulconis Cappellani dicti domini Comitis; in 1197, the Codice Diplomatico della Lombardia medievale records dominus Kiroldus, filius domini Fulconis, de Fabiano. As a trace of its transformation into a surname, Rossoni cites the artist Alessandro de Fulco, documented in Naples at the beginning of the 16th century.

Blunda highlights the historical figure of Fulk V of Anjou (1092–1143), count of Anjou and Maine, who acceded to the throne of Jerusalem in 1131 by marrying Melisende, heiress of the Latin kingdom. He also notes that the variants Furco and Furcone reflect a consonantal metathesis characteristic of southern Italian, while Fulcone incorporates an Italian augmentative suffix.

Rossoni places the presence of the surname in a scattered way in the centre and south of Italy, with a zone of origin clearly identified in Sicily and possible foci in the Turin area and in Liguria. The variants Fulcon, Fulcone, Fulconi and Fulconis are extremely rare.