Napier City councillor Rob Lutter will resign next week, after being approached to lead a national charitable foundation.
Mr Lutter, a fourth-term councillor, recently accepted a position as chief executive of @Heart, a charity which supports New Zealand children and families affected by congenital heart disease. He will resign onMay 22.
"It's a cause which is close to me. My son Zac was born 17 years ago with multiple heart defects and he has since undergone 15 heart operations, four of which were open heart surgery," Mr Lutter said.
He said it was a tough decision to leave the council but the job was an opportunity he could not turn down.
"It will be hard to leave Napier City Council. It has been an honour to represent the people during the past nine years but I don't want to be a part-time councillor. I don't think it would be fair to the people of Napier.
"Most of my time has been with Barbara [Arnott] and I'm really proud of the things we did with her as mayor, she was a wonderful leader. I see Bill [Dalton] doing some great things for Napier, too, and wish council all the best going forward. It has been a pleasure to serve the people of Napier for nine years."
He said some of the highlights of his time as a councillor included construction of the waste-water treatment plant, scheduled to be completed mid year, and the upgrade of the Taradale shopping centre. He was a mayoral candidate in last year's local body elections.
While the job was based in Auckland, he planned to commute between the two cities, as his family would remain in Napier.
"It's important to me to be able to attend next week's council meeting so I can formally announce my plans for the future to my colleagues."
Mayor Bill Dalton said Mr Lutter had made a valuable contribution to Napier and he wished him well.
"Rob's been fantastic to have around the council table. He has been a passionate advocate for our city and I know that passion will serve him well in his new role, too."
Napier City Council chief executive Wayne Jack said a by-election would be held.
