On his Facebook page, Mr. Berlusconi wrote on Friday, “Only those who were close to me during these years know what I have suffered as a result of this unfair and ignominious accusation.” Courtroom testimony had focused on raunchy “bunga bunga” parties, involving many aspiring starlets, at the home of Mr. Berlusconi, a media mogul and the leader of the Forza Italia party.

Stating that he was “deeply moved,” Mr. Berlusconi also uncharacteristically thanked the Italian judiciary — an institution he has repeatedly attacked over the years as the perpetrators of unrelenting legal persecution. The ruling “gave a confirmation of what I have always said: that the vast majority of Italian magistrates do their job quietly, with admirable impartiality and rigor.”

Though the legal victory vindicated Mr. Berlusconi, it is unlikely to herald his return to power.

“I think Berlusconi is basically out of the political game,” said Sergio Fabbrini, director of the school of government at Luiss Guido Carli University in Rome, citing the former prime minister’s age and the fact that he is serving community service and is on trial in another court in Naples. Friday’s acquittal “is a specific and contingent success for him, but it isn’t a comeback. There are too many things on his shoulders that make it impossible for him to play a senior role in Italian politics.”

However, the ruling fortifies Mr. Berlusconi’s position as the center-right’s principal interlocutor with Prime Minister Matteo Renzi in negotiations to reform Italy’s Parliament. The current, unwieldy system has been cited as a main obstacle to enacting much-needed social and economic changes. Opponents to the reforms — which include changing the country’s bicameral parliamentary system, the electoral system and the relationship between the regions and central government — have tried to use Mr. Berlusconi’s legal problems to weaken his bargaining power.

“Those who opposed the pact between Renzi and Berlusconi can’t boycott it anymore, so from the point of view of Italian democracy it’s an important ruling,” Mr. Fabbrini said. “Now Berlusconi has more legitimacy in the center-right to demand discipline and that they follow his line,” that is “the political heritage Berlusconi can leave.”