It’s understood he has taken the decision for family reasons.
The Donegal senior championship semi-finalists are now advertising for a new manager.
But friends of Campbell say he won’t be applying for the role this time around.
In a statement the club thanked him and his back room team for their work over the past two years.
Applications to replace him must be with the club’s secretary by Friday, November 28.
The club’s AGM is on December 13.