Dr Paul Blantern took over at the authority in 2007 and has overseen a raft of changes in recent years amid successive council tax freezes.
A fortnight ago he penned a joint report with council leader Councillor Heather Smith (Con, Oundle) calling for the Government to iron out local authority funding inequalities across the country.
At the current rate of supply, Northamptonshire will have made Â£500 million of cuts in the decade between 2010 and 2020 just to balance the books.
In the last few minutes, Dr Blantern has announced his intentions to stand down from the Â£185,000 a-year-post.
In an email sent to staff, he wrote: "It is with mixed emotions that I write to you today to let you know that I will be leaving Northamptonshire County Council this month after ten highly rewarding and enjoyable years at the authority.
"Last week I met with the leader of the council Councillor Heather Smith and we agreed together that having overseen the move to our new headquarters building, completed the recruitment and design of our new management team and transformed the operating model of the council, now would be an appropriate time for me to leave the organisation to take on new challenges.
"I am certainly excited as I embark on the next stage of my own career but at the same time will sorely miss the energy, commitment and spirit that defines this council. I know that we continue to find ourselves in a highly challenging financial situation but I also know that we have achieved so much innovation and transformation which has truly put Northamptonshire at the forefront of local government practice in so many areas."
Dr Blantern said he intended to serve a short notice before leaving.
"It would be better for the longer-term decisions the council needs that I leave sooner, and have agreed the date of 13th October," he said.
"This will enable a quick transition. An announcement regarding the management of the organisation from the 16th will be made shortly."