Today Facebook announced that Donald Graham, chairman of the board and Chief Executive Officer of The Washington Post will join Facebook’s board of directors next month. This isn’t a surprising giving the strong connection between Mark Zuckerberg and Donald Graham who was also one of the first investors (I’m currently confirming this) in Facebook.

Donald Graham joined the Washington Post in 1971 as a reporter and has switched among positions within the news and business industries. This news means Facebook now has four other board positions outside of Mark Zuckerberg filled: Marc Andreesen, Jim Breyer, Peter Thiel, and now Donald Graham. With five total board seats, the board of directors is now filled at Facebook.

Mark Zuckerberg has been intelligently providing his top mentors with board of directors positions. Historically, Zuckerberg has had an extremely tight relationship with Donald Graham. When interviewed by the Times Online in October of this year, Zuckerberg was asked “Who is or was your mentor?” His response was:

Donald Graham, chief executive officer and chairman of the board of The Washington Post. He takes a very long-term view on business. So much of technology is focused on a really short cycle.

As such, it’s not very surprising to see this final board position given to Graham. Given that Facebook is one of the leaders in new media, Graham is nicely positioned to make a smooth transition from a leading role in traditional media to a leading role in new media.