The authors agree that this surname has a Greek origin, derived from the root kal-, meaning "beautiful, good". P. Durante and G. P. Holmes simply note its meaning of "beautiful". V. Blunda specifies that it comes from the Greek calàs, "beautiful, good person", and that it functioned originally as a nickname applied to the ancestor for his beauty or good character, before becoming a family surname.

G. Rohlfs links it specifically to the Greek surname Chalàs, still current in Greece, and frames it within the Byzantine presence in southern Italy (6th–11th centuries) and the survival of the Griko communities of Calabria. E. Rossoni documents its transformation into a surname in the 13th century in Martirano, in the Catanzaro area, with Giovanni and Enrico Calà in the retinue of Emperor Henry VI.

As for its geographical distribution, Holmes places it as typical of Sicily, with notable presence in the Caltanissetta area —especially in San Cataldo and Mussomeli—, as well as in Randazzo, Bronte and Catania, Tortorici in Messina, and Canicattì in the Agrigento area. Rossoni also notes it as characteristic of Sicily, while Rohlfs associates it with Calabria.