Tony Hall, a former director of BBC news, will replace George Entwistle, who resigned as director-general this month after failing to get to grips with a crisis which threw the 90-year-old state-funded organisation into turmoil.
Hall's immediate task will be to rebuild the confidence and image of a news organisation buffeted by the fallout from a scandal centred on former BBC presenter Jimmy Savile, who died at 84 last year and has since been exposed as one of Britain's most prolific, predatory child abusers.
"I care passionately about the BBC, about what it can do, its programme makers and the impact we have," Hall told reporters.
"It's one of those extraordinary organisations which is an absolutely essential part of the UK, of Britain, of who we are, but also has this incredible impact around the world, too."
Chris Patten, chairman of the BBC Trust which overseas the broadcaster and appoints its director-general, said Hall had been the only candidate approached, but denied there had been any external pressure to rush the appointment.
"I'm delighted that in moving fast we've also managed to find the out-and-out outstanding candidate," said Patten, who has warned that the future of the publicly-funded broadcaster was at risk unless it underwent radical reform.
"If we'd spent the next four months on this, you would have all been telling us we were off our trolleys and quite properly as well," he added.
A series of senior BBC managers have stood aside while investigations continue into serious editorial failings, leaving the broadcaster vulnerable to claims it lacks leadership.
Patten said Hall was "the right person to lead the BBC out of its current crisis" and that his journalism experience would be "invaluable as the BBC looks to rebuild its reputation".
Hall, 61, who will take up the role in March, left the BBC shortly after missing out on the top job in 2001.
He will also face the task of streamlining an overly bureaucratic institution accused by its journalists of being top-heavy with multiple layers of management.
Entwistle lasted just 54 days in the job, quitting after the BBC's flagship programme Newsnight wrongly claimed a senior Conservative politician had been involved in child sex abuse.
The broadcaster last week paid £185,000 pounds in settlement to Lord Alistair McAlpine, a former treasurer of Britain's Conservative party, who had faced public opprobrium on the heels of the Newsnight report.
Repercussions from the flawed programme have spread beyond the BBC. Commercial rival ITV agreed on Thursday to pay McAlpine 125,000 pounds after a chat show presenter showed a card with the names of alleged sex abusers during an interview with Prime Minister David Cameron.
McAlpine is also pursuing Twitter users who sent messages over the social network naming him.
Entwistle had been widely criticised for lacklustre leadership in dealing with disclosures on Savile and Newsnight's dropping of an investigation into the late presenter last year, shortly before the BBC broadcast programmes in tribute to him.
"The past eight weeks have been very traumatic for the BBC but this is a significant day ... (that) marks the beginning of a new phase," Patten said.
Hall's appointment was widely greeted as a sound choice, although there were some concerns at his limited experience outside the publicly-funded sector.
"I'm delighted. I think he's a very wise appointment," Roy Greenslade, professor of journalism at London's City University.
"He's a rare combination: someone who rose very high at the BBC, but who's also done well outside it."
John Whittingdale, chairman of parliament's media committee, said the Trust had been sensible to move quickly in making a new appointment but he questioned whether Hall would be able to deal with reforming BBC bureaucracy.
"That, possibly, is an area where Tony Hall doesn't have experience and there might have been a case for somebody with more external management experience," Whittingdale told Reuters.
