Italo Gismondi trained as an architect; however he is better known as a leading archaeologist. Entering the Italian culture ministry, he was named director of the excavations at Ostia, a post that he held for over 40 years. His architectural background enabled him to make a particular study of ancient building practices and design. It also helped him in his work on the recreation of buildings from fragmentary remains; one of his legacies is the first detailed map of the monuments of the Roman Forum, published in 1933.
He was responsible for restoring a portion of the Baths of Diocletian in Rome, including the 'Planetarium'; he also created the model of ancient Rome (at the time of Constantine) that is now in the Museo della Civiltà Romana at EUR. He also worked on excavations in Abruzzo, Molise and Sicily, and in Libya.