Mr Zuckerberg and 27-year-old Priscilla Chan tied the knot at a small ceremony at his home in Palo Alto, California, capping a busy week for the couple.
The tech mogul took his company public in one of the most anticipated stock offerings in Wall Street history on Friday, which saw the social network valued at $104billion.
And Ms Chan graduated from medical school at the University of California, San Francisco, on Monday, the same day Mr Zuckerberg turned 28.
The couple met at Harvard and have been together for more than nine years.
A source at the wedding said Mr Zuckerberg designed the ring featuring ‘a very simple ruby’.
The ceremony took place in Mr Zuckerberg’s backyard before fewer than 100 guests, including Facebook’s chief operating officer Sheryl Sandberg.
The guests all thought they were coming to celebrate Ms Chan’s graduation but were told after they arrived that the event was in fact a wedding.
‘Everybody was shocked,’ the source said.
Rather than his trademark hoodie, Mr Zuckerberg wore a suit for the ceremony, while his bride wore a traditional wedding dress.
Food was served family-style and included dishes from the couple’s favorite Palo Alto sushi restaurant.
The two had been planning the marriage for months but were waiting until Ms Chan had graduated to hold the wedding, according to the source.
The timing was not tied to the IPO, he added, since the date the company planned to go public was a ‘moving target’.
Despite his strong advocacy of online openness and sharing, and scant regard for web users’ desire for privacy, Mr Zuckerberg has long been secretive about his own personal life.
It was not even widely known that the Facebook founder was engaged to Ms Chan, despite the length of their relationship.
Even after Friday’s IPO, Mr Zuckerberg remains Facebook’s single largest shareholder, with 503.6million shares.
And he controls the company with 56 per cent of its voting stock.
The site, which was born in a dorm room eight years ago, has grown into a worldwide network of almost a billion people.
Mr Zuckerberg founded Facebook at Harvard in 2004, in a saga which would later become the basis for Oscar-winning film The Social Network.
He was named as Time’s Person of the Year in 2010, aged just 26.
Mr Zuckerberg grew up in Dobbs Ferry, New York.
