The Nantucket case was one of a series of sexual misconduct allegations against Mr. Spacey that came to light in the early days of the #MeToo movement, which followed revelations about the behavior of the Hollywood producer Harvey Weinstein. Numerous powerful men have lost their jobs after people they harassed or assaulted felt emboldened to speak out; Mr. Spacey’s acting career came to a sudden halt, with “House of Cards” cutting him out of the final season and the film “All the Money in the World” replacing him with Christopher Plummer in the role of J. Paul Getty.

But the accusation out of Nantucket was the only one against Mr. Spacey that had led to criminal charges. Other than a coming trial against Mr. Weinstein in Manhattan involving two women and a charge of indecent assault and battery against the celebrity chef Mario Batali in Boston, few other #MeToo cases have been brought in the United States. In most instances, the incidents were either too old to prosecute or did not rise to the level of a criminal offense.

Mr. Spacey’s accuser had reported to the police that in July 2016, when he was 18 and working as a busboy at the Club Car restaurant in Nantucket, he had asked to be introduced to Mr. Spacey one night after his shift ended.

After he and Mr. Spacey had had several drinks, the young man said, they began to sing together at the piano. The accuser said that Mr. Spacey had been trying to get him to come home with him, and that while they were standing by the piano, Mr. Spacey had unzipped the young man’s pants and rubbed his penis for about three minutes, according to a police report.

When Mr. Spacey went to the bathroom, the young man told a woman at the bar that he thought Mr. Spacey was trying to rape him, and when she advised him to leave, he ran home, according to his account to the police.

Mr. Spacey was charged in December 2018 with one count of indecent assault and battery in the case. He pleaded not guilty, and his lawyer, Alan Jackson, argued that the encounter with Mr. Spacey was “consensual flirtation.” Mr. Jackson wrote in a court filing that the accuser “concocted and exaggerated elements of a story to impress his friends.” Mr. Jackson did not respond to a request for comment on Wednesday.