As a State institution the Museum was born in 1883 and as such belongs to a significant historical moment when newly unified Italy undertook the founding of national institutions. The government did not fail to show a timely and appropriate interest in supporting a ‘national' art.

The Museum's first three decades were spent at the Exposition Palace constructed by Pio Piacentini in 1883. The Museum's current seat goes back to 1915. Monumental, but spacious as well, the building was created by Cesare Bazzani for the exposition celebrating the fiftieth anniversary of Italian unification in 1911. The site's suburban area, beyond the city walls and Porta del Popolo, began its development at that time, taking the name Valle Giulia.

The collection was presented following a criteria organized around regional schools but allowing for the exposition of important foreign artists as well. The works were acquired at the great National Expositions and at the international Biennale of Venice. Such works represent the best of what was at that time officially admitted: a great deal of Symbolist, Neo-renaissance Decadentist, Italian verismo and a few nods towards the Secessionist movement as well.

Additionally there were a number of important donations and bequeaths by protagonists of the then recently ended 19th century; works prevalently of the Southern schools by Morelli, Palizzi and Celentano.

In the years ensuing the end of the First World War to the end of the Second World War the panorama of the Contemporary collections accented a national and a regional nature. Acquisitions regarding the 19th century also focused on the ‘national' artists critically favoured at that time. These were oriented towards romantic intimacy: Macchiaoli, Divisionists and the sculptural work of Medardo Rosso. In 1933 and 1934 the architect Bazzani returned and expanded the building but until 1945 these new spaces were devoted exclusively to works celebrating the tenth anniversary of Fascism.

Soon the Gallery would acquire the autonomous status of Superintendent and from the mid 1940's until 1975 was under the supervision of Director Palma Bucarelli (1910-1998). These were fertile years where the Gallery was closely allied to the methodologies of the Roman University school. First with Lionello Venturi, and later with Giulio Carlo Argan the Gallery acquired international prestige thanks to a museography of wide breadth encompassing timely and relevant expositions by the likes of Picasso, Mondrian and Pollock, to mention only a few. There were new acquisitions of works by international masters of the Twentieth century,such as Mondrian, Modigliani, Moore and Pollock, for example, as well as essential Italian artists like Burri, Colla, Capogrossi, Fontana, Manzoni and the Kineticists. In the 1960's the collection was re-ordered, underscoring its abundance and even its apparent completeness.

Paradoxically the departure of Bucarelli along with the birth of the new Ministry of Culture deprived the Gallery of its independence regarding acquisitions. Reduced to the level of its fellow Superintendents, the following twenty years were characterized by a notable decline in promoting the contemporary in art. However this was compensated by a noteworthy policy of acquisitions geared towards filling in the missing blanks regarding pre-unification Italy; the first half of the 19th century. Such were the works acquired: historical, romanticist and purist by artists such as Palagi, Koch, Gastaldi, Ciseri and Franchi. Important donations followed one another in quick succession with series of works by Italian masters of the 20th century - above all Balla, De Chirico, Guttuso. There were new museums acquired as well: house-museums of collectors of the 19th and 20th centuries such as the Praz and Boncompagni museums and artists' studios of the 20th century such as those of Manzù and Andersen.

A first sign of renewed attention to the contemporary came in 1995 under Minister Paolucci with the acquisition of a group of works from the 1980's by exponents of the Transavanguardia movement. Regarding the generation of the 1990's Superintendant Pinto promoted the initiative "Partito preso" (Taking sides) a program with roots going back to Bucarelli's time which focused on the encouragement of young artists.

The National Gallery of Modern Art has thus acquired the status of "mother museum", that is to say the museum of the 19th and 20th centuries.