The authors agree that De Marco is a patronymic surname that derives from the name Marcus, of Latin origin, linked to the Roman god of war, Mars. F. Miranda specifies that Marcus would be a syncopated form of Marticus, derived from Mars, and notes that the name Marco was frequently imposed on children born in March, the month consecrated to that god.

F. De Laurentiis highlights that the name became consolidated also by the prestige of the cult of Saint Mark the Evangelist, especially in the northeast of Italy, in the regions of Veneto, Friuli-Venezia Giulia and Trentino-Alto Adige, and places the greatest presence of the surname in Lombardy and in Emilia-Romagna. Miranda, on the other hand, indicates that De Marco is more widespread than its variant Di Marco and that it predominates in the southern regions, in particular Calabria, Puglia, Campania, Sicily and Basilicata. In Sicily it is recorded in all the provinces, with greater concentration in the Catania, Messina and Palermo areas.