[1][2] After Bologna, Fiocco returned to Sapienza University of Rome where he undertook postgraduate art history studies under Adolfo Venturi, receiving his diploma in 1911.
Because of his travels, as early as 1909 Fiocco was familiar with impressionist works, particularly those owned by collector Marcell Nemes in Munich.
[1] In 1954 Fiocco was appointed as the first director of the Institute of Art History of the Giorgio Cini Foundation in Venice, serving in that position until his death.
[1][2][4] Under his leadership the institute became a major center for research into Venetian art by publishing catalogues of the collections of the Fondazione Querini Stampalia and the civic or city museums of Belluno, Treviso, and Vicenza; funding scholarships and exhibitions; and establishing a library and photo library at its headquarters on San Giorgio Maggiore.
[1] Fiocco's own research and writings focus on Venetian and Florentine art, artists, and patrons, with a special interest in Luigi Cornaro, Andrea Mantegna, Palla Strozzi, and Paolo Veronese.