The deal, signed overnight, aims to save €3.0 million a year by cutting overtime pay and bonuses and boosting productivity, and includes a promise by unions not to strike over issues linked to the deal.
"This is a victory for the Teatro dell'Opera di Roma," the opera's superintendent, Carlo Fuortes, said in a statement, praising the seven unions representing the musicians and staff for "shouldering responsibility".
The opera house, housed in a 19th-century building in the centre of the Italian capital, had vastly expanded its international reach over the last decade or so.
But it was plagued by bad management and debt, which led to mass ticket cancellations this year, putting its very future at risk.
The Opera's management presented a plan in July to save the company, which was approved in September by some 460 employees.
But after a few tense months during which two of the smaller unions continued to threaten to strike, primary conductor Riccardo Muti threw in the towel, saying that after six years in the job there was no longer the "necessary serenity" to lead successful productions.
The management announced in October that 182 choristers and musicians would be fired and hired back as freelancers during the opera season, a threat which forced the unions back to the negotiating table.
Rome's mayor Ignazio Marino welcomed the new deal and said he hoped that "in time", 73-year-old Muti could be persuaded to return.
In the meantime, Verdi's Aida, which the Neapolitan native was set to conduct to open the season on November 27th has been cancelled and replaced with Dvorak's Rusalka, conducted by Norway's Eivind Gullberg Jensen.