Saget, 62, shared a photo from the big day's beach celebration at Shutters on the Beach in Santa Monica, California.
"Okay, so we went and did it. And damn are we happy," he captioned the post. In the photo, the lovebirds smile with the beach in the background.
Saget wore a classic black suit while Rizzo, 39, donned a sheer lace gown that Us Weekly reports was designed by Pronovias.
Rizzo also shared a photo taken by photographer Nicole Goddard, writing, "@Bobsagt and I dressed up as bride and groom for Halloween. Seriously though, best day of my life."
From the looks of things, there were multiple celebrity guests in the audience, including musician John Mayer, who also shared an Instagram post about the big day.
"Like I said, I had a thing last night. And what a beautiful thing it was. Congratulations Kelly and Bob!" the 41-year-old, who pushed his Instagram live show back three hours Sunday night for the wedding, wrote.
Saget said he thought he'd never find love after divorcing from his first wife Sherri Kramer, with whom he shares three daughters, in 1997.
"I didn't think I'd have a relationship again," he told Closer Weekly. "I was kind of in that 'just work, make people happy and take care of your kids until they're 90' mindset." But he knew after meeting Rizzo through a mutual friend that she was the real deal.
He told PEOPLE after their engagement in November last year that he kept it casual when he popped the question.
"We were watching Stranger Things on the iPad," he said at the time. "And then I got up to go to the restroom, and I opened the safe and I took out a ring that I had been hiding for four days and I got on one knee. And she said, 'What are you doing?' and she got very emotional and so did I."
The two celebrated in Beverly Hills with friends Katie Killean and former Seinfeld producer George Shapiro. Rizzo called her ring "my new favorite accessory."
Saget hinted that they wouldn't opt for a super quick engagement, telling Andy Cohen on Watch What Happens Live last year that "I just want to enjoy the engagement a whole lot."