Jon Parker has been appointed on an interim basis, following the departure of Rebecca Sandles.
The news comes as the Independent Police Complains Commission arrested an officer from the force over the alleged passing of information to a journalist.
Parker, who will report to assistant commissioner Frank Armstrong, takes on the role for at least three months after being made redundant from a similar role at Wiltshire Police late last year.
He said: 'I'm coming in to provide some leadership and look at how we all operate and whether we can do things that will make us more dynamic moving forward. There is a lot of good work going on here already.'