In 2024, we meet the 140th anniversary of birth of Grigory Alexandrovich Vereshchagin, the head of the Leningrad Military Library of the Workers and Peasants’ Red Army (RKKA), which today bears the name “Information Historical and Scientific Center – Military Historical Library of the General Staff of the Armed Forces of the Russian Federation”. The biography of G. A. Vereshchagin, who headed the Library from 1924 to 1934, actually preserved it in the difficult post-revolutionary years and strengthened its position as one of the central libraries of the Military Department, was not previously been the subject of special study. The purpose of the article is to present, based on the results of the reconstruction of G. A. Vereshchagin’s life and professional path, his contribution to the formation and development of the Library in the Soviet period of national history. As a result of the analysis of a wide source base, previously unknown facts of G. A. Vereshchagin’s life related to his studies, military service, and activities as the head of the Leningrad Military Library of the Red Army were established. Some aspects of the history of the Library headed by him were revealed: dates and procedure for its reorganizations in 1924-1932, sources of replenishment of collections, the most important of which were the State Book Stock and the Obligatory Copy of military literature, which entered the Library in 1925-1930. It is shown that the main activities of G. A. Vereshchagin as the director of the Library were: the formation of library collections, the organization of work on the creation of alphabetical and systematic catalogs, the development of the classification scheme of the Military Department of the Library. For the first time, archival documents related to G. A. Vereshchagin’s life and work are introduced into the scientific circulation, the history of his ex-libris creation is revealed.