Open to all forms of culture, the Gerolamo is the theater of the Milanese: of all the Milanese, young and old, curious and passionate, of those who want to have fun lightly, and of those looking for a starting point in the art to reflect. It hosts theatrical performances, puppets, exhibitions, and concerts, in a space-favor in the heart of Milan.

The Gerolamo was built in 1868 on the site of a previous theater of the same name, derived from the famous puppet Gerolamo, during the post-unification reorganization of the center of Milan. The theater, entirely made of wood, had two tiers of boxes, the gallery and the stalls, for a total of six hundred seats. It was basically the puppet theater of Milan, and also the hall where the companies of the dialect theater performed.

From 1911 the management was entrusted to the company of Carlo Colla, exponent of the famous dynasty of Milanese puppeteers, who held it until 1957.

In 1958 the management passed to the Piccolo Teatro of Milan, which used the small hall above all for the recitals of great actors and singers: Franca Valeri, Lilla Brignone, Tino Buazzelli, Jean-Louis Barrault, Laura Betti, Paolo Poli, Dario Fo and Franca Copper, Ornella Vanoni, Juliette Gréco, Domenico Modugno, Paola Borboni. In 1962 the recital Milanin Milanon was staged, which re-proposed the traditional Milanese songs chosen by Roberto Leydi, together with poems by the major local dialect authors, all directed by Filippo Crivelli. Interpreters of the show were Milly, Tino Carraro, Enzo Jannacci, Sandra Mantovani and Anna Nogara. From 1960 the hall also became the seat of the stable company of the Milanese theater of Piero Mazzarella and Carlo Colombo and then became the main seat of the Milanese dialect theater.

From 1978 to 1983 the theater was directed by Umberto Simonetta, who made it a theater room in Milan but not in dialect. Among the most successful shows of this period was the 1978 comedy I wanted Strehler with Maurizio Micheli. The Gerolamo was forced to close in 1983, because it was a theater made entirely of wood, and therefore incompatible with the new safety regulations.

In 2017 the reopening after a long restoration. Today the Gerolamo has 209 seats.