But defense lawyers said the women had willingly had sex with Mr. Weinstein to further their careers. Only years later, his lawyers said, after Mr. Weinstein had become a symbol of the #MeToo movement, did the women say their encounters with him were not consensual.

The defense presented evidence that Ms. Haley and Ms. Mann not only had friendly communications with Mr. Weinstein after they said they were attacked, but they also had sex with him.

After deliberating for five days the jury, seven men and five women, determined that Mr. Weinstein had broken the law.

The verdict was a victory for the Manhattan district attorney, Cyrus R. Vance Jr., whose legacy is likely to largely be defined by the outcome of the case. He came under heavy public pressure to prosecute Mr. Weinstein after declining to do so in 2015, when an Italian model said the producer had groped her breasts at a business meeting.

The earlier decision came back to haunt Mr. Vance in late 2017 when dozens of women came forward to accuse Mr. Weinstein of sexual misconduct. The district attorney became a target of protests, even as Mr. Weinstein went on trial last month.

After the verdict was announced, Mr. Vance said that the women who testified against Mr. Weinstein “changed the course of history in the fight against sexual violence” and that society owed them “an immense debt.”

“The women, who came forward courageously and at great risk, made that happen,” he said. Mr. Weinstein, he added, was “a vicious serial sexual predator who used his power to threaten, rape, assault, trick, humiliate and silence his victims.”