Before his time at the Museum of Fine Arts, Marzio was an assistant professor at University of Maryland.
In his time there he helped historian Daniel J. Boorstin with research for his Pulitzer Prize-winning book The Americans: The Democratic Experience.
[5] After this, Marzio served in various roles at the Smithsonian Institution (curator of prints and chairman of cultural history).
Additionally, he contributed to the creation of the MFAH's Rienzi, a house museum on a four-and-a-half acre estate dedicated to European art donated by Henry Masterson III.
[12] Additionally, Marzio wrote two books on lithography–in 1976, The Art Crusade: An Analysis of American Drawing Manuals, 1820–1860 and, in 1979, The Democratic Art—Pictures Pictures for a 19th-Century America: Chromolithography, 1840–1900.
His death was announced and a moment of silence was held during a Monday Night Football game being played by the Houston Texans.
"[13] Kaywin Feldman, president of the board of trustees of the Association of Art Museum Directors said, upon hearing of Marzio's passing, "I think the era of the aloof, supercilious museum director has long passed, and that our jobs are much more about openness and accessibility."