When asked what he looks for in a prospective employee, the social network's founder said: "I will only hire someone to work directly for me if I would work for that person.
"It's a pretty good test and I think this rule has served me well."
He added: "Facebook is not a company for everyone in the world."
The entrepreneur, who is worth around $35bn (£22.9bn), was speaking at a question-and-answer session the Mobile World Congress in Barcelona.
Facebook is one of the toughest technology companies to get hired by, because it has a relatively small staff compared to other Silicon Valley firms.
Mr Zuckerberg said: "The most important thing is to keep your team as small as possible.
"Facebook serves more than a billion people around the world but our team has fewer than 10,000 people. It's only possible because of modern technology. Big companies get bloated."
Among those hand-picked to work at the company by Mr Zuckerberg is Sheryl Sandberg, the chief operating officer.
He told the audience he considered her a mentor who had helped him create a "healthy organisation".