The surname Macario reflects the cult of Saint Macarius, derived from the Greek name Makarios, which means "blessed" or "happy". Saint Macarius is the name of several important saints in the history of Christianity, the best known being Saint Macarius of Egypt and Saint Macarius of Alexandria.

In Italy, the name Macario appears in several localities, often connected with old religious settlements or churches dedicated to Saint Macarius. San Macario in Piano, for instance, is a locality in the region of Tuscany. But these surnames could also derive from place names such as Macherio, in the Milan area, called Maccario in ancient times, or other localities dedicated to Saint Macarius.

Historical forms of the surname such as Maçarius exist, which show the evolution of its pronunciation in the local dialects.

The variants of the surname and their particular features

1. Macario: found mainly in Piedmont, especially in Boves and Cuneo. In Italy the surname is distributed across 284 municipalities, with the greatest concentration in Turin.
2. Maccario: predominantly Piedmontese and Ligurian, with a significant group between Ventimiglia and Soldano, in the Imperia area. It may derive from place names such as Macherio.
3. Macari: has its largest core in the Frosinone area, between Castelnuovo Parano and Casalattico.
4. Maccari: found throughout central and northern Italy, with a presence also in Cetraro, in the Cosenza area.