Kent's Police and Crime Commissioner Ann Barnes has announced she will not be standing for re-election in May.
Ms Barnes was elected as an independent candidate in 2012 but has been a controversial figure during her tenure.
In a statement on her website, Ms Barnes said: "I am content that I have delivered what I said I would."
She said she had made several promises when elected, all of which she had kept, including ensuring victims and witnesses came first and preventing the politicisation of the PCC role.
"I have also raised the profile of police and crime commissioners - not always in the way that I intended," she said.
Ms Barnes also noted her proudest achievements were the establishment of a dedicated sexual assault referral centre in Maidstone and the crime victim support centre in Ashford.
The former Kent Police Authority chairwoman said she had now spent more than 15 years in police accountability and governance.
"Fifteen years service in this intense and all-consuming role is probably long enough," she said, adding that Kent Police was in "a very strong and sustainable position for the future".
Ms Barnes said it would be "business as usual" until her term of office finished on 11 May.