BBC Trust chairman Chris Patten is calling for the public broadcaster to undergo a thorough overhaul of its structure and management.
The British Broadcasting Corporation's director-general, George Entwisle, stepped down on Saturday after a controversial report on current affairs show Newsnight led to a former Conservative Party treasurer being wrongly accused as a child abuser.
Lord Patten said they had several conversations about the situation, but Mr Entwistle decided himself to resign and he did not to argue him out of it, the BBC reports.
Lord Patten said a new director-general would be chosen within weeks and that he intends to stay on to restore confidence in the broadcaster. He said the BBC had to ensure that programmes were being properly managed.
The BBC Trust has appointed Tim Davie as acting director-general, who joined the BBC as head of marketing and who was due to take up the role of chief executive officer of BBC Worldwide.
Before his departure, Mr Entwistle had commissioned a report from BBC Scotland director Ken MacQuarrie into what happened with the Newsnight investigation and is expected to report on Sunday.
On 2 November the current affairs programme reported abuse victim Steve Messham's claims against a leading 1980s Tory politician being an abuser in north Wales, but he withdrew his accusation a week later, saying he had been mistaken.
Lord McAlpine, although not named on Newsnight, was identified on the internet as the subject of the allegations and said the claims were "wholly false and seriously defamatory".
Lord Patten, appearing on the BBC's Andrew Marr programme, said his own job was to show licence fee-payers "that the BBC has a grip, that we get ourselves back on the road".
Of Mr Entwistle's departure, he said: "He's editor-in-chief of a great news organisation and I think he felt he should take responsibility for the awful journalism which disfigured that Newsnight programme. One of the ironies is that he was a brilliantly successful editor of Newsnight himself for some time."
Mr Entwistle lasted just 54 days on the job, but Lord Patten praised him as "a very, very good man, cerebral, decent, honourable, brave".
He said it was too soon to talk of cutting Newsnight but said there was an "argument" for the BBC to look at giving the head of news a stronger role.
Meanwhile, Lord Patten has also tried to rally staff, insisting that he is committed to rebuilding trust and confidence in the corporation. In a letter to staff, he said he he still believed that the BBC is the greatest broadcaster in the world.