The authors agree that the surname originates in a name of Germanic root. E. Rossoni notes that it derives from the Norman name Gesoaldo, of Lombard matrix, and documents its fixing as a surname in the Salerno area from the second half of the 13th century, with Mattia Gesualdo as lord of Caggiano. V. Blunda, for his part, describes a Germanic origin from the compound Gis Vald, formed by gis ("arrow, dart") and vald ("power, command"), with the meaning "ruler of the arrow" or "lord of the shaft". Blunda adds that the root gis appears in numerous personal names such as Giselberto or Gisela.

Blunda highlights the figure of Carlo Gesualdo da Venosa (1566–1613), prince and composer, who transformed late-Renaissance madrigal music with chromatic harmonies that anticipated modern musical language, and whose life was marked by the double murder of his wife and her lover in 1590.

As for geographical distribution, Rossoni indicates that Gesualdi shows isolated pockets in the province of Foggia —in Panni and in the provincial capital—, in the Potenza area —in Latronico— and in Tuscany, between Prato and Montemurlo. Gesualdo, by contrast, has a more extended presence in Apulia, with clusters in Foggia and in the Bari area —Altamura, Bitonto and Gravina in Puglia—, as well as an isolated pocket in Catanzaro and another in Sicily, in Mazzarino.