New Zealand High Court judge Lowell Goddard has been named as the head of a new inquiry into historical child sex abuse in England and Wales.
The inquiry will have statutory powers and a new panel, Home Secretary Theresa May told the House of Commons.
Mrs May said she was determined to "expose despicable crimes".
Since the original child abuse inquiry was set up last July, two chairwomen have resigned amid concerns over their links with the establishment.
Mrs May said Justice Goddard was "as removed as possible from the organisations and institutions that might become the focus of the inquiry".
Peter Saunders, chief executive of the National Association for People Abused in Childhood, said Justice Goddard would "enhance the whole credibility of the inquiry".
Justice Goddard, who was appointed to the New Zealand High Court in 1995, said she was "committed to leading a robust and independent inquiry".
The Auckland-born judge has previously led an inquiry into police handling of child abuse cases in New Zealand.
By Clive Coleman, BBC legal correspondent
A statutory inquiry established under the Inquiries Act 2005 has considerably more powers than its predecessor.
Justice Goddard will be able to compel witnesses to attend and give evidence, and force them to provide documentary evidence.
Those powers mean that some witnesses and "core participants" - ie those who may have played a significant role in relation to the matters being examined, have a major interest in those matters, or face explicit criticism from the inquiry - are likely to "lawyer up".
That can make the process much longer.
The inquiry will be looking into serious criminality, so Justice Goddard will have to steer a careful course between a rigorous inquiry and ensuring that future criminal trials are not prejudiced.
The original inquiry was sparked by claims of paedophiles operating in Westminster in the 1980s.
The inquiry will investigate whether "public bodies and other non-state institutions have taken seriously their duty of care to protect children from sexual abuse in England and Wales".
'No stone unturned'
Mrs May said Justice Goddard was a "highly respected" member of the judiciary and an "outstanding candidate with experience in challenging authority in this field".
"We must leave no stone unturned if we are to take this once in a generation opportunity to get to the truth," she said.
Justice Goddard will face a "pre-appointment hearing" before the Home Affairs Committee of MPs on 11 February to ensure "further transparency", Mrs May said.
She also said there would be a "co-ordinated national policing response" to "follow up any lead the inquiry uncovers".
And she said the decision to select a new panel was "by no means a criticism of the current panel members".
Justice Goddard said she was "honoured" to lead the inquiry and was aware of the "scale of the undertaking".
"The many, many survivors of child sexual abuse, committed over decades, deserve a robust and thorough investigation of the appalling crimes perpetrated upon them," she said.
By Dominic Casciani, BBC home affairs correspondent
Last year's catastrophic double failure to launch the abuse inquiry posed serious questions for the home secretary and her team.
The new inquiry's chief is a world away - geographically and institutionally - from the characters and parts of the British state that victims insist must come under uncomfortable scrutiny.
Justice Goddard's appointment echoes the decision to use a Canadian judge to look into some of the most controversial allegations levelled at the state in Northern Ireland: in both of these cases the government has concluded it could only win the broad support of victims by asking a complete outsider to step in.
Theresa May's statement made clear she has personally learned some hard lessons about transparency and trust.
The attention now turns to Justice Goddard who will have to prove that she has the legal skills, stamina and empathy to expose historical abuse - but also the independence to stand her ground amid the clamour.
Justice Goddard said the inquiry would act without "fear or favour" and would "hold those responsible to account".
BBC home affairs correspondent Danny Shaw tweeted: "It's understood Theresa May personally interviewed Lowell Goddard by video-link before deciding to appoint her as #CSAinquiry chair."
Labour MP Simon Danczuk, who called for a statutory inquiry, welcomed the appointment of Justice Goddard and said work should now begin before the general election in May.
"It is clear that mistakes have been made with this inquiry in the past, but I think today shows that we are moving in the right direction and I hope we can all now focus on the future," he said.
Baroness Butler-Sloss, Mrs May's first choice as inquiry chairwoman, resigned a week after it was set up. She faced calls to quit because her late brother, Sir Michael Havers, was attorney general in the 1980s.
Her replacement, Lord Mayor of London Fiona Woolf, stood down on 31 October amid concerns over her links to former Home Secretary Lord Brittan.
Abuse inquiry: How we got here
1 July 2014 - MP Simon Danczuk calls on former Home Secretary Leon Brittan to say what he knew about paedophile allegations passed to him in the 1980s
7 July - Government announces independent inquiry into the way public bodies investigated and handled child sex abuse claims. Baroness Butler-Sloss chosen as head
9 July - Baroness Butler-Sloss faces calls to quit because her late brother, Sir Michael Havers, was attorney general in the 1980s
14 July - She stands down, saying she is "not the right person" for the job
5 September - Lord Mayor of London Fiona Woolf named the new head of the inquiry
11 October - Mrs Woolf discloses she had five dinners with Lord Brittan from 2008-12
22 October - Abuse victim launches legal challenge against Mrs Woolf leading the inquiry, amid growing calls for her resignation
4 February 2015 - Justice Lowell Goddard, a serving judge of the High Court of New Zealand, announced as the new head of the inquiry