Born in Rome in 1874, Luigi de Gregori was among the most prominent Italian librarians of the first half of the twentieth century. After working as a Latin and Greek teacher, he entered the library sector in 1903, beginning his work at the National Central Library of Rome.

From 1922 to 1923 he served as director of the Archeology and Art History library of Rome (BiASA). He later became director of the city’s Casanatense Library, where he remained until 1935.

In 1926 he published numerous articles across various newspapers denouncing the poor conditions of Italian libraries, promoting instead the Anglo-Saxon public library model. These pieces led to the creation of an executive board within the Ministry of Education dedicated expressly to libraries.

Appointed chief library supervisor in 1935, he served a leading role in operations concerning the protection of Italian libraries’ most valuable books during World War II. Launched in 1936, these protection plans allowed for books to be moved to storage sites far from potential military targets in the event of war. De Gregori was initially responsible for choosing a depository for library books from Rome and the region of Lazio. Later, following Italy's entry into the war, he became head of all storage operations in Italy, above all taking care to directly verify, through on-site visits, the state of conservation of books, as well as the security conditions of each storage site.

At the end of 1942, with intensified bombings in Italy having severely damaged several libraries in Turin and Genoa, De Gregori found it necessary to include a wider breadth of material in the sites, books initially protected via the simple removal from shelves and relocation to library basements. Thus, to the ten sites created at the start of 1943, eleven were eventually added to house hundreds of thousands of books and manuscripts in need of protection.

With Italy’s surrender on September 8, 1943, and the subsequent establishment of the Italian Social Republic, the Italian public administration was moved from Rome to northern Italy. De Gregori remained in the Italian capital with a small group of employees from the Ministry of Education to coordinate security operations for libraries in central Italy.

In the days surrounding the Allied landing in Anzio (January 22, 1944), De Gregori was able to restore to Rome valuable library material from the city’s libraries that had been stored in the Abbey of Santa Scolastica in Subiaco, securing it in the Vatican; the Germans had set up a military hospital in the abbey, rendering it unfit for safekeeping. Indeed, the site was bombed by Allied forces in May 1944.

With military fronts crossing the nation, De Gregori worked to ensure that directors of national libraries were granted authority to make quick decisions in case of danger, and not be dependent on Ministry approval.

After the Liberation of Rome, De Gregori contacted the MFA&A Subcommission to secure the return of Neapolitan library materials that had been seized by German forces in October 1943 and deposited in Rome following various alterations.

In 1946 he personally oversaw the return of materials from German libraries in Rome and Florence, which had been removed by German forces in 1943 and transferred to Austria.

He died in Rome on October 4, 1947.