Mr Ullyot has been Facebook’s vice president, general counsel and secretary since October 2008, according to BusinessWeek.
Before joining Facebook, Mr Ullyot was a partner at Chicago-based Kirkland & Ellis, and also served as chief of staff at the US Justice Department and as a deputy assistant to President George W Bush.
In a statement, Facebook said Mr Ullyot had been a ‘valued’ member of its leadership who ‘built our legal team through an intense five-year period in which we faced complex and high-stakes legal issues of all types’.