Designing the theatre, Sfondrini paid particular attention to the acoustics, conceiving the interior structure as a "resonance chamber", as is evident from the horseshoe shape in particular.

With a seating capacity of 2,212, the house had three tiers of boxes, an amphitheatre and two separate galleries, topped by a dome adorned with frescoes by Annibale Brugnoli.

For a brief period the theatre was managed by Costanzi's son, Enrico, who gained renown by organizing another great premiere, that of Tosca by Giacomo Puccini on 14 January 1900.

Chief among several major changes was the relocated entrance, from the street formerly known as Via del Teatro (where the garden of the Hotel Quirinale is now) to the opposite side, where Piazza Beniamino Gigli exists today.

The interior was embellished by new stuccowork, decorations, and furnishings, including a magnificent chandelier measuring six meters in diameter and composed of 27,000 crystal drops.

Above the proscenium arch is a plaque commemorating the rebuilding: "Vittorio Emanuele III Rege, Benito Mussolini Duce, Lodovicus Spada Potenziani, Romae Gubernator Restituit MCMXXVIII—VI”".

Rome City Council again commissioned architect Marcello Piacentini, who radically altered the building's style, notably with regard to the facade, entrance and foyer, each of these taking the form we know today.

The stucco work was completely restored, the great proscenium arch strengthened, and a parquet floor of solid oak blocks laid to replace the previous one.

Notable productions under Muti have included Gluck's Iphigénie en Aulide (2009), Verdi's Nabucco (2011), Simon Boccanegra (2012) and Ernani (2013).