Democratic Senator Al Franken will leave office on Jan. 2, a spokesman for the Minnesota lawmaker said Wednesday.
Franken announced his plans to resign earlier this month in the wake of several sexual harassment allegations, but did not announce a date.
He said earlier Wednesday that he would deliver a series of speeches on the Senate floor before he leaves the chamber.
Franken will be replaced by Minnesota Lieutenant Governor Tina Smith, also a Democrat.
The demise of Franken's Washington tenure unfolded over the past few weeks. It was touched off by claims made by a Los Angeles radio host and former model, Leeann Tweeden. She accused Franken of forcibly kissing her when they both were on a 2006 tour to entertain U.S. troops in the Middle East.
Tweeden posted a picture of a smiling Franken holding his hands over her breasts while she was sleeping on a return flight to the United States.
Franken apologized to Tweeden, but soon after other women also accused the one-time television and film comedian of unwanted advances.
He variously apologized, said the incidents did not occur or said he remembered the encounters differently. But as the allegations mounted, dozens of his Democratic colleagues in the Senate demanded that he resign.
Franken announced his resignation in a defiant speech on the Senate floor earlier this month, saying it was ironic that he was quitting even as President Donald Trump remains in office after more than a dozen women accused Trump during his 2016 campaign of unwanted sexual advances.
Trump, a Republican, says none of the accusations against him is true, but he is facing new calls from Democratic lawmakers to answer the specific allegations. Six senators, all Democrats, have called for his resignation.