Mason announced her resignation last week, after two years in the role, and it was accepted at a closed extraordinary council meeting on Monday.
The City of Onkaparinga, South Australia's largest metropolitan council, has announced the appointment of Mason as its new chief executive.
Mason's last day at Selwyn District Council will be January 16.
She will be paid out her notice period of three months.
Selwyn District Council strategy, engagement and capability executive director Steve Gibling has been appointed the acting chief executive.
Gibling will take over from January 16.
The council agreed to deputise the mayor and deputy mayor to enter into negotiations with Gibling regarding the terms for the interim chief executive position.
Selwyn Mayor Lydia Gliddon said Mason’s resignation “was a shock”.
There had been speculation the resignation was due to a clash with the new council's direction, but Gliddon said it was simply down to Mason being "offered an opportunity elsewhere”.
“We are on really good terms.
“She has navigated us through the induction period and been really supportive.
“She’s just got a great opportunity and needs to take it.”
Gliddon acknowledged Mason’s contribution to the district
“Sharon has led this organisation through a period of significant change, strengthening internal processes and positioning Council for a successful future.
"Her leadership has been instrumental in delivering key projects and ensuring Selwyn continues to thrive. We thank her for her dedication and commitment to our community. Sharon has another exciting opportunity on the horizon, and we wish her every success in this next chapter.”
Gliddon said Gibling is a calm, practical leader "with deep knowledge of council operations and extensive experience in local government".
"Since joining Selwyn District Council, he has demonstrated his capability during multiple periods as acting chief executive, providing continuity and stability as we work through the annual plan and other key priorities.
"His proven ability to maintain strong working relationships with councillors and staff reflects his dependability and integrity.”
- By Jonathan Leask
Local Democracy Reporter
