"This is entirely behind me," Weiner told a news conference, just hours after he confirmed exchanging sexually explicit photos and text messages online. "There was no question that what I did was wrong," he added.
He resigned his Congressional seat in June 2011 after acknowledging having sexual correspondence, including a photo of a man's bulging underwear, with at least a half-dozen women. In recent months, he has re-emerged to become a leading candidate for mayor. The New York Times and three of his rivals for mayor called on Weiner to drop out of the race.
The 48-year-old Weiner acknowledged some of the activity took place as recently last summer, more than a year after he resigned from Congress — and after he and his wife sat down for a glowing People magazine profile in which they said their troubles were behind them.
"I said that other texts and photos were likely to come out and today they have," Weiner said in a statement issued by his campaign earlier in the day. He also said "some things posted today are true and some are not," but he did not elaborate.
His wife, Huma Abedin, a longtime adviser to former U.S. Secretary of State Hillary Clinton, stood by him during his comments, at times smiling nervously, and made rare public statements on her husband's behaviour.
"I love him. I have forgiven him. And as we have said from the beginning, we are moving forward," Abedin said. She acknowledged that Weiner "made some horrible mistakes, both before he resigned Congress and after." She did not appear with him at the raucous news conference when he stepped down from Congress.
On Tuesday, Harper's Bazaar released an excerpt from a piece Abedin wrote explaining that although she doesn't like the limelight, she decided to campaign for her husband because he's "a better man" now.
Abedin, whose parents are Indian and Pakistani and who spent most of her childhood in Saudi Arabia, was pregnant when the sexting scandal broke in 2011 and gave birth months later. "It took a lot of work and a lot of therapy to get to the place where I could forgive Anthony," she said.
After they walked away from the news conference, out of sight of the crowd, Weiner put his arm around her. He then attended a mayoral forum on gay issues and was warmly received.
The new allegations could severely test voters' willingness to forgive Weiner, who has said he spent the two years since the original scandal trying to make things right with his wife and earn redemption.
The newly revealed correspondence was posted Monday by the gossip website The Dirty. The woman involved was not identified. She said their online relationship began in July 2012, when she was 22, and lasted for six months.
She claimed Weiner used the alias "Carlos Danger" for their exchanges, but she knew she was talking to the former congressman.
The woman claimed that she and Weiner exchanged nude photos of themselves and engaged in frequent phone sex. The Dirty ran a pixelated photo of what appears to be a man's genitals.
The exchanges posted on The Dirty consist of sexually explicit fantasizing about various sex acts. At one point, the man reported to be Weiner wrote, "I'm deeply flawed."
"This was a bad situation for me because I really admired him. Even post scandal, I thought he was misunderstood. Until I got to know him. I thought I loved him. Pretty pathetic," the woman was quoted as telling the website.
The woman said Weiner later asked her to destroy the evidence of their chats. She insisted that she never had sex with Weiner or received any payment from him.
Since re-entering public life this year, Weiner has apologized repeatedly for his behaviour.
The original scandal began when a website run by conservative commentator Andrew Breitbart posted a photograph of a man's bulging underwear and said it had been sent from Weiner's Twitter account to a Seattle woman. Weiner denied he sent the photo, claiming his Twitter had been hacked.
But after more women came forward and more photographic evidence emerged, Weiner admitted he lied.
Also on HuffPost