Mercati was born in Reggio Emilia (precisely in the village of Villa Gaida) from a middle-class family.
[5] Among his disciples were Giuseppe Schirò (professor at the University of Padua and then at the Sapienza, after Ciro Giannelli's brief experience),[6] Enrica Follieri (Schirò's successor) and Bruno Gentili, who later specialized in archaic Greek poetry.
He wrote several short articles and notes, and a monograph – the critical edition of Ephrem's Greek sermons.
[12] His disciple (and successor) Enrica Follieri cited "l'originalità, l'erudizione, la brevità" [originality, erudition, brevity] as the most evident characteristics of Mercati's production.
[13] Starting from 1908, Mercati signed his publications as "Giuseppe Silvio" to distinguish himself from his older brother Giovanni, who also was a Byzantine scholar – since the two shared the same initial of first name; from his edition of Ephrem's texts in 1915, he inverted the two names, and since then he wrote Silvio Giuseppe Mercati.