Mark Thompson, who has run the BBC since 2004, has announced that he will step down as director general sometime in the fall after the completion of the BBC's coverage of the 2012 London Olympics and the Queen's Jubilee.
As director general, Thompson oversaw the BBC's extensive TV, radio, Web and digital operations.
His departure comes at a crucial time for the BBC, which will be facing a major review of its operations and funding in 2016.
Thompson announced his departure in a lengthy letter to staff. "When Chris Patten became BBC Chairman last year, I told him I thought there was a strong case for handing over to a successor sooner rather than later," he noted. "From the point of view of the BBC, I thought that my successor should have time to really get their feet under the table before the next Charter Review process got going."
The corporation already faced some heavy layoffs and budget cuts during Thompson's tenure.
No exact time has been set for his departure but Thompson noted he has been the longest serving director general since the 1970s.
Despite the funding cuts and such controversies as "Sachsgate" and "Crowngate," Thompson argued in his departure letter that "it's because of your efforts that the BBC I will be leaving is so much stronger than the BBC I inherited back in 2004. Trust and approval are at record highs, our services are in brilliant creative form and we've demonstrated beyond contradiction that the BBC can be just as much of a leader and innovator in the digital age as we once were in the analogue one. Now more than ever, to audiences at home and abroad the BBC is the best broadcaster in the world."
In a statement, Lord Patten also praised Thompson, calling him an "outstanding" leader.
In an article on Thompson's departure, the Guardian noted that the executive change could lead to the "first female director general, with BBC chief operating officer Caroline Thomson and head of news Helen Boaden among the leading internal candidates, along with head of BBC Vision, George Entwistle."