“Sheryl has been my partner in running Facebook and has been central to our growth and success over the years,” Zuckerberg said in a statement. “Her understanding of our mission and long-term opportunity, and her experience both at Facebook and on public company boards makes her a natural fit for our board.”
Sandberg said she is "deeply passionate" about Facebook's mission to make the "world more open and connected."
The company had a disappointing initial public offering last month. The stock sunk soon after its market debut, although it has since re-gained some of its value.