ROME — For nearly a year, Pope Francis remained mostly silent in the face of a searing accusation by a former papal ambassador to the United States that he knew, and did nothing about, the sexual misconduct of former Cardinal Theodore McCarrick — a silence that fueled criticism that he was tone deaf on the issue of sex abuse that was plaguing his church.

But in an interview published Tuesday, just weeks after Francis issued the first law requiring that officials in the Roman Catholic Church worldwide report cases of clergy sexual abuse to their superiors, he directly denied the accusation.

“About McCarrick I knew nothing. Obviously, nothing, nothing,” he said in the wide-ranging interview with the Mexican television network Televisa, a transcript of which was also published by the Vatican’s own news outlet, Vatican News. He added that before a church investigation reported the misconduct, “I knew nothing, no idea.”

Last August, Archbishop Carlo Maria Viganò, a former ambassador to Washington, said that he had personally told Francis about penalties imposed on Mr. McCarrick, a former archbishop of Washington, by the pope’s predecessor, Benedict XVI.