The theatre was built mainly of tuff, and concrete faced with stones in the pattern known as opus reticulatum, completely sheathed in white travertine.

[4] The network of arches, corridors, tunnels and ramps that gave access to the interiors of such Roman theatres were normally ornamented with a screen of engaged columns in Greek orders: Doric at the base, Ionic in the middle.

In the Early Middle Ages the theatre was used as a fortress of the Roman family of Faffo or Fabi (called "from Pescheria") and then at the end of the 11th century (when it was known as templum Marcelli), by Pier Leoni and later his heirs (the Pierleoni).

Later, in the 16th century, the residence of the Orsini, designed by Baldassare Peruzzi, was built atop the ruins of the ancient theatre.

The Embassy of the Sovereign Military Order of Malta to the Holy See is located in the premises of Casa Litta – Palazzo Orsini, in Teatro Marcello.