Stroici's rescue was initially described as an exceptional feat by firefighters who had worked late into the night. Rescue teams used drones and rubble clearers to try to reach him, despite the risk that the fragile tower could collapse further.
He had been conscious and talking to the emergency workers throughout the rescue. His wife was also at the scene.
Romania's foreign ministry sent its condolences to his family and said "together with them, we held on to hope until the very last moment".
Stroici had been carrying out conservation work on the medieval tower just off Rome's busy Via dei Fori Imperiali and close to the Forum itself, one of this city's busiest tourist sites. This particular building had been empty and abandoned for many years.
The Rome Prosecutor's Office has opened an investigation into the incident.
Part of the structure collapsed at about 11:20 on Monday and efforts to rescue Stroici were interrupted when a second section of the 29m (90ft) high tower began crumbling again about 90 minutes later, as bricks rained down, creating a huge cloud of dust.
Rome prefect Lamberto Giannini had described it as a "very complex situation". After the initial collapse he said firefighters had "put up some protection" around the trapped man, so that when the second collapse happened, "they obviously shielded him".
He added that the rescue was a long operation due to having to "mitigate... the enormous risks faced by the people trying to carry out the rescue".
One firefighter was taken to hospital with an eye problem, according to Italian reports, but the rest were unharmed, eventually resuming their search for the man.
A police chief said there was no imminent danger that the tower would disintegrate.
"My thoughts and deepest sympathies go out to the person currently fighting for his life beneath the rubble, and to his family, for whom I sincerely hope that this tragedy finds a positive outcome," wrote Italian Prime Minister Giorgia Meloni on X before the rescue was complete.
