But he says he still has more to do and is standing for an eighth term as Invercargill's leader.
One of the country's most recognised names and faces, Mr Shadbolt is also a public speaker, comedian, actor, author, commentator and former concrete contractor and commune founder as well as a local politician.
He moved to Invercargill in the early 1990s and has three adult sons plus a fourth, Declan, who is 4.
Why are you standing for mayor?
It is one of the most difficult jobs you can possibly have because you are often the court of last resort for people with problems, but at the same time it is the most rewarding job you can have, because you can make a difference.
Will you be a full-time mayor, and why?
No, not really. I think it is good to have other interests and hobbies outside of council work. But you are never really not a mayor.
You're always going to be confronted wherever you go. I might take my little boy to soccer, but invariably some other parent on the sideline will go ''excuse me Tim, I don't like to intervene, I know this is not the appropriate place, but ...''
Then they go on to describe whatever problem they may have. It is much more than 40 hours a week that you put in to being mayor.
What position do you think the city is in?
I'm a born-again optimist. I think you have to be as mayor. You have to believe in the future of your city. Not only am I am optimist, I get an insight into projects happening around the city.
You get to see behind the scenes. You see how a city works.
You see how you dispose of sewage without polluting the environment, how you dispose of rubbish, how you get clean water to people's houses, how you create roads which are as safe as possible, how parks are designed and so on.
To me it is fascinating. As an ex-concrete contractor I am interested in the practical side of local government.
What are three issues facing the incoming council, and why?
The first is local government reform. There have been attempts at amalgamation, which have all failed because the people have voted against them, and so the Government has decided to take that voting right away.
Amalgamation creates uncertainty and anxiety, and stops progress and new ideas in its tracks, because you've just got to focus all your ideas on amalgamation.
I went through the great purge of 1989, when 700 councils were reduced to 70, and I saw exactly what happened. Nothing got done for a whole year while we tried to sort ourselves out.
Southland already collaborates well. The three mayors get on famously. We have such a good collaborative rubbish and recycling system here that Local Government [New Zealand] has chosen to send [council chief executive] Richard King and [councillor] Lindsay Thomas to go round the Pacific Islands looking at how they can improve their systems.
The second issue is fighting for a reduction in electricity transmission pricing and getting a fair deal for southern businesses and consumers.
The third challenge will be infrastructure. I actually believe our population could increase by more than what the Southland regional development strategy is attempting to do, which is 10,000 people in 10 years.
No-one saw the growth in Auckland coming. It sounds like a pathetic joke, but I actually think that having too many people in Southland is going to be something an incoming mayor is going to have to face.
What is one thing you would like to have achieved by the end of your term, and why?
I guess it would have to be the survival of local government and our city in approximately its present form. A few changes here and there is fine, but the legislation [being proposed] would allow for one city for the entire South Island, and there would be nothing we could do to stop it.
