The chief constable of Strathclyde Police has been appointed to lead the new Police Service of Scotland.
Stephen House, 54, is expected to take up his role with the new force, which formally comes into being next April, in the autumn.
His appointment was confirmed by the Scottish Police Authority.
Mr House said he was "delighted" to accept the £208,000-a-year role which will see him lead the UK's second largest police force.
Speaking after his appointment was confirmed, Mr House said: "My views on the creation of a single Police Service of Scotland have been widely publicised so it gives me great professional pride to be trusted with the responsibility for developing and leading the new service.
"The priority for the new service will be to continue keeping people safe in Scotland and there will be no let up on the work to tackle organised criminality, violence and all the other issues which are of concern to our communities.
"Local policing is a vital part of this and I am determined that it will be at the heart of the Police Service of Scotland ethos."
Mr House strongly hinted that the force mergers would not be without some pain.
He said: "There are changes to make and these will not be easy. We need to organise ourselves better.
"We need to tackle inconsistencies in national systems and procedures, while backing the local discretion of commanders to deal with local issues.
"I am proud of the achievements that have been made in tackling crime in recent years and I look forward to working with and learning from my colleagues from other forces to bring these together and provide the best possible service for the Scottish public."
Scotland's current eight regional police forces are being merged into one, under a government drive to save cash without hitting front-line operations.
The new chief constable will take charge of what will be the second largest force in the UK, behind the Metropolitan, with more than 17,000 officers.
The force will formally come into being on 1 April 2013. Mr House is expected to take up his role in October.
The appointment was confirmed by Vic Emery, chair of the Scottish Police Authority, whom said both he and Mr House were "entering new and uncharted territory" that was "challenging and exciting".
He said: "This is a historic moment in Scottish policing and together we have an opportunity to shape both the operational delivery of policing and the governance of policing to meet the complex challenges of the 21st century, and deliver improved outcomes for the people of Scotland.
"We recognise and welcome the huge responsibility we have been given."
Following his appointment, Justice Minister Kenny McAskill said Mr House had the necessary "skills and experience" and would be "an outstanding first chief constable".
"He has an impressive track record of leadership, partnership working and delivery," the justice minister said.
Mr MacAskill has said previously that there would be no compulsory redundancies as a result of the unified force, which will provide employment for about 6,500 support staff.
Trade unions, however, believe about 3,000 posts could go.