The building occupied by the Museo Nazionale del Bargello began as an assertion of civic government in thirteenth-century Florence. Founded in 1255 beside the older Volognana tower, it was the city's first purpose-built public palace. It housed the Capitano del Popolo, an official intended to represent the organized citizenry and counterbalance aristocratic power. Soon afterward it became the seat of the podestà, Florence's chief magistrate. Coats of arms mounted around the courtyard commemorate the succession of officials who governed and judged cases within its walls while the Florentine republic expanded through commerce, factional struggle, and war.

Political violence repeatedly touched the palace. Its tower bell summoned citizens during emergencies and civic assemblies. A fire in 1323 damaged the complex, after which an additional story was constructed. The courtyard, external stair, council chambers, and chapel developed through later medieval campaigns. The Chapel of Mary Magdalene was decorated with frescoes attributed to Giotto and his workshop, including an early portrait traditionally identified as Dante Alighieri. The image carries special resonance because Dante had been condemned and exiled by the Florentine government whose judicial world the palace embodied.

Under Medici ducal rule the building acquired the name by which it is now known. In 1574 Cosimo I's son Francesco transferred the podestà's functions and installed the bargello, or chief of police. The palace became police headquarters and a prison. Cells occupied its rooms, interrogations and trials took place there, and executions were carried out in or near the courtyard. For centuries the building represented the coercive authority of the Tuscan state. In 1786 Grand Duke Pietro Leopoldo abolished the death penalty and torture in Tuscany, a landmark legal reform, but the Bargello continued to serve as a prison until the mid-nineteenth century.

After the prison closed, restoration between 1859 and 1865 sought to recover the palace's medieval appearance. Italy's political unification gave the project a new purpose: the former seat of judgment became one of the new nation's first museums. The Museo Nazionale del Bargello opened in 1865, initially displaying objects connected with Florence and the Middle Ages. Transfers and acquisitions soon made it the principal national collection of Italian sculpture. Works by Donatello, Michelangelo, Verrocchio, Cellini, Giambologna, and the della Robbia workshop were gathered in spaces once used by magistrates and jailers.

Among the museum's most consequential objects are Lorenzo Ghiberti's and Filippo Brunelleschi's competition panels for the Florence Baptistery doors, products of the celebrated 1401 contest often associated with the emergence of Renaissance art. Donatello's bronze David and Michelangelo's Bacchus similarly connect the palace to decisive changes in European sculpture. The Bargello's history is therefore not simply that of a collection placed in an old building. The structure itself charts Florence's passage from communal republic to Medici state, from prison regime to unified Italy, and from a center of punishment to a public institution devoted to the artistic achievements that made the city famous. The museum's installation also preserved memories of the building's harsher uses. Stone walls, barred openings, the chapel, tower, and heraldic courtyard remain part of the visitor's experience, allowing civic justice, imprisonment, and artistic patronage to be interpreted together rather than separating Florence's political history from its celebrated Renaissance culture.