Gianfranco Donelli obtained his master degree in Biological Sciences from the Sapienza University of Rome in 1966. From 1967 onwards he worked as researcher at the Istituto Superiore di Sanità (ISS - Italian National Institute of Health) in Rome in the field of molecular biology and ultrastructure of bacteriophages and human intestinal viruses. In 1975 he was appointed Director of the Electron Microscopy Unit and in 1979 he became the Research Director in molecular biology. In 1982 he founded the Laboratory of Ultrastructures of ISS that has been led by him till 1996. In those years his main research interests covered many aspects of cellular microbiology with special reference to the mechanism of action and the pathogenetic role of toxins and other bacterial virulence factors. He has been invited since 1977 to serve as visiting professor in the Universities of Ancona, Naples, Perugia, Rome and Urbino and in 1999, he was habilitated as full Professor of Microbiology.  

Regarding his scientific assignments, Professor Donelli has been appointed Coordinator of the Infectious Diseases Research Project of ISS (1991-1995); Vice-President of the Advisory Committee for Biological and Medical Sciences of the Italian National Research Council (1994-1999); International Affairs Officer of the Italian Society of Microbiology and FEMS delegate (2002-2022); President of the Society for Microbial Ecology and Disease (2006-2009),Vice-Chairperson of the Executive Committee of ESCMID Study Group for Biofilms (2009-2013) and Director of the Microbial Biofilm Laboratory at the Fondazione Santa Lucia research hospital in Rome (2000-2022). In the last two decades, his research activity has been mainly focused on biofilm-based healthcare-associated infections and the possible strategies to prevent and counteract the development of microbial biofilms in the human body.

Professor Donelli is in the list of the Top Italian Scientists in Biomedical Sciences as author of over 210 full-length papers published in international journals (H-index = 60) with more than 13350 citations, and editor of a number of books.