At a full council meeting yesterday, Mr Martin (63) formally announced his resignation as of November 2, saying, while his contract ran until February 2013, his retirement was timed to allow the council plenty of time to find his replacement and allow that appointee input into the next year's annual planning process.
"It's a rather unique opportunity to plan around a transition that is good for the work programme and allows for smooth continuation ..."
If needed, he would leave later, to ensure there was no gap in leadership, Mr Martin said.
"I'm very flexible about time.
It's appropriate to retire earlier, so the council can be supported through to 2013 and a local government election."
Chairman Stephen Woodhead said the resignation came as no surprise as Mr Martin had indicated his intentions last year.
Its timing was a reflection of Mr Martin's professionalism and passion for the council and the region.
As Mr Martin had been chief executive since 1993, his knowledge of the Resource Management Act, Local Government Act and the region would be "hugely missed", Mr Woodhead said.
"Thanks to Graeme's leadership, the Otago Regional Council has a very professional, experienced and dedicated staff, who are a key part of the core values and principles that underpin what the council is and how we operate."
The process for recruiting a new chief executive would start immediately and the council would hire a consultant to assist in the process, he said.
Councillors had yet to discuss what skills they needed from a new chief executive. There was a possibility an international search would be conducted.
After the meeting, Mr Martin said his retirement would allow him to spend more time on his lifestyle block at Earnscleugh and with family.
"In this job you have to put 110% in it, so first I have to get 100% out of it."
He would not be standing for council or "recycling" himself as a hearings commissioner.
"I know what I don't want to do."
Cr Duncan Butcher, who along with Cr Louise Croot, was part of the council that recruited Mr Martin, said it was a sad occasion as it had been a long relationship.
"I've talked to him to try and change his mind about retiring," Mr Butcher said.
Mr Martin had made his mark on the council through his leadership during major issues the council had faced and on the direction the council had taken in those 19 years, he said.
Cr Butcher hoped the policies the council was still working on would be cemented before Mr Martin left.
"Graeme, I hope you work to double the speed to get to that position."
Councillors praised Mr Martin's professionalism and dedication to the job.
"It's typical of you to always think ahead, to think of the organisation instead of yourself," Cr Michael Deaker said.
"In my about 50 years of public service there has been none other that has had more dignity, mana, sheer ability, than you."