Zuckerberg's net worth is now $81.6 billion, around $373 million more than Buffett.
Facebook's stock closed at a record on Friday, gaining almost 5 percent as the company shook off the effects of a privacy scandal that engulfed it earlier this year. Facebook allowed political strategy firm Cambridge Analytica - which helped Donald Trump's campaign - to harvest the private data of 87 million users.
While Warren Buffett has built his fortune using smart investing tactics and putting money in the right places, Mark Zuckerberg has built a social media empire out of Facebook, his creation from his college days.
Facebook appears to have made it through its worst storm to date, though.
The social network's shares soared to an all-time intraday high of $203.64 a share, before closing at a new record just below that price.
Technology fortunes make up about a fifth of the more than US$5 trillion in wealth tracked by the Bloomberg index, more than any other sector. Apple is now one of Berkshire's largest holdings. The legendary investor has donated about 290 million Berkshire Hathaway Class B shares to charities, most of which went to the Bill & Melinda Gates Foundation. The Facebook CEO's worth has risen by around $19 billion in a little over three months, after a steady downfall in the wake of the data privacy scandal, days before the comeback.
Zuckerberg passed Buffett Friday as Facebook shares rose 2.4 percent, Bloomberg reported.