"Luann and Tom looked so happy. They really got to have fun with all their guests. It was a New Year's Eve to remember! You can really tell how much they love each other. Their friends couldn't be happier for them," a source told the website.
De Lesseps had revealed on "The Steve Harvey Show" in December that her wedding would be "a three-day affair."
She and D'Agostino kicked off the celebrations with a rehearsal dinner Friday and hosted a post-wedding brunch at The Colony Hotel in Palm Beach on Sunday.
"The Real Housewives" star shared several posts from the weekend on Instagram, including a video from her rehearsal dinner.
She followed up Monday with a photo of herself and D'Agostino leaving brunch for their honeymoon.
"We're off! Happy 2017! #weddingweekendfun," she captioned the snapshot.
De Lesseps was previously married to Alexandre de Lesseps and shares two children, Noel and Victoria, with her ex-husband.
She confirmed in August that she and D'Agostino would still wed despite him kissing another woman.
"I'm not going to let a stupid kiss ruin the rest of my life," the star told People. "He screwed up. What he did was wrong. But this wasn't premeditated. It wasn't an affair. It was a mistake."
Copyright 2017 United Press International, Inc. (UPI). Any reproduction, republication, redistribution and/or modification of any UPI content is expressly prohibited without UPI's prior written consent.