Roberto Cassio was born in Rome on June 22, 1964. He started learning about mosaic art and restoration in his free time at a very young age under his father's guidance.

After graduating as a surveyor in 1983 he worked until 1988 at the "Studio Cassio" where he participated in restorations of ancient mosaics scattered across various archaeological sites under the protection of the superintendents of Rome and many other territories throughout Italy. From 1989 to 1999 he owned the independent company "Mosaic Restoration Laboratory" where he crafted small and large mosaics for Italian and foreign clients in addition to his restoration work. Since 1993 he has been responsible for the Vatican Museums’ mosiac restoration laboratory. Simultaneously he continues to craft numerous works specializing especially in those performed in the ancient tradition of the Roman yarn mosaic. From 2011 to 2019 he participated as a lecturer in the "Mosaic Conservation Course", a MOSAIKON program on the initiative of the Ghetty Foundation, Ghetty Conservation Institute, ICCROM, ICCM and carried out by the Center for Archaeological Conservation of R. Nardi

In 2014 and 2020 on commission of the Philippine embassies at the Holy See and the Order of Malta respectively, he made two mosaic panels inserted into the Vatican gardens that depict Marian images.