Neal Mitchell, a Labour member, has left Newark & Sherwood Council after five years as a councillor.
The news was announced Coun Penny Rainbow, council chairman, who sent her best wishes to Mr Mitchell on behalf of the authority.
Coun Paul Peacock, Labour Group leader, told a full council meeting: “It is fair to say Neal was universally liked across the council with members and staff colleagues.
“He was an excellent councillor, but also had things to contribute to the economic development committee.
“Up until the last few years with Covid, Neal was extremely active and always had something positive to contribute.
“It was a difficult decision for him, it was the right decision for him.
“We should all put our families first and Neal has done that. In doing so he stayed true to his values and his nature.”
A by-election date will be set in due course.