Lincolnshire Police Deputy Chief Constable Neil Rhodes will temporarily take on the role of Chief Constable, the Police Authority announced.
He will take over the role from Chief Constable Richard Crompton, who will retire at the end of March.
Alec Wood, who left Lincolnshire Police in 2010 to work as Assistant Chief Constable in Derbyshire, will return as temporary Deputy Chief Constable from April 2.
Assistant Chief Constable (Safer Neighbourhoods) Keith Smy will continue in his present role.
Chief Supt Roger Bannister will replace Carl Langley as Assistant Chief Constable (Protective Services), while Assistant Chief Constable (Safer Neighbourhoods) Keith Smy will continue in his present role.
Police Authority Chairman Barry Young said: “Following the announcement of Richard Crompton’s retirement and Carl Langley’s promotion to ACC with another Force, we have moved very quickly and positively to ensure continuity and stability within the Chief Officer team.
“I am delighted that we have been able to put such a strong team together at a time when policing faces so many challenges. The people of Lincolnshire can be confident that the new team is more than up to the job.”
Chief Constable Neil Rhodes said: “It’s an enormous privilege to be asked to lead Lincolnshire Police as Chief Constable.
“When I first stepped out on the beat, as a young constable patrolling the streets in Lincoln 26 years ago, I hoped I might make it to inspector before I retired, so you can image the pride I feel today.
“With fewer officers and a tight budget the year ahead will be pretty challenging. My personal priority will be retaining officers on the beat and PCSOs in the heart of the community.
“In your area your local officers should be known to you, and it’s important you feel confident of a friendly ear and a prompt response when you need to speak to them.
“Lincolnshire is a very safe place to live, work and spend your leisure time. We need to keep crime low and our streets places we can all walk with confidence.
“Lincolnshire Police achieve that by being closely connected with the community we serve, earning trust and support.
“I intend to work hard to retain that support, trust and confidence over the months ahead, and to ensure the officers and staff of this force are well led and well motivated to do the same.”