Ian Read. left, will leave the Local World-owned weekly on 15 March to join Tower Hamlets Council in East London.
He will be replaced as editor of the Courier by Roger Kasper, until now editor of sister title the Sevenoaks Chronicle.
Courier Media Group said an announcement about Roger’s successor would be made in due course.
Ian, 31, joined the Courier as a trainee reporter in December 2002 and was appointed its editor a little over six years later.
He said: “I have loved every minute of my time at the Courier and being editor of such a respected newspaper has been a great honour.
“Particular highlights of my time as editor include helping raise thousands of pounds for a blind toddler, successfully campaigning to keep Crowborough Athletic in their division, winning the fight to keep parking free in Cranbrook and lobbying hard for the A21 dualling to go ahead.”
“The Courier has been at the heart of local life for 140 years and it will continue to do so in the multi-media age. I look forward to keeping an eye on local goings-on as a Courier reader: I may even contribute the occasional reader’s letter!”
During Ian’s four years as editor, the Courier was named best weekly newspaper in the South of England at the 2011 EDF Energy Media Awards, and last month collected the Campaign of the Year trophy at the Kent Media Awards for the paper’s A21 campaign.
Before being appointed Courier editor, Ian was in charge at the Sevenoaks Chronicle, where the paper picked up an award for its campaign to reopen the town’s theatre.
A statement from the Courier Media Group said: “We wish Ian every success in his future career and take this opportunity to thank him for his significant contribution to the business.
“Roger Kasper will take over the editorship of the Courier from 15 March and an announcement about the editorship of the Sevenoaks Chronicle will follow in due course.”