He filed his nomination yesterday and said his decision was partly prompted by the number of people who had approached him in the past year asking him to stand again.
"If I'd had any doubts whatever about going back again for a fourth term, that would have firmed up my decision."
Dr Macpherson said he had no "sense of completeness" about his work as mayor.
"In the next term of the council, Contact is likely to decide on which option for the hydro dams it is going to pursue.
"There could be coal mining in the Manuherikia and I expect a wind-farm application back before us again.
"There's some meaty stuff to deal with in the next term and I have the track record in these things that would be useful.
"If I look back over the nine years I've been mayor there's quite a long list of achievements I've had a hand in, and I'm happy to be judged on those."
So far, only one other candidate has thrown his hat in the ring - deputy mayor Tony Lepper.
Dr Macpherson will also stand for the Southern District Health Board.
"There's only four people to be elected from Otago and I think it'll be a struggle for rural people to get on, so I'm not overly hopeful about getting back on."
He also plans to stand for Central Lakes Trust, which is a charitable trust covering the area of the former Otago Central Electric Power Board.
Nominations for trustees open on Thursday and the election will be held in November.
Four of the current six trustees have served the maximum number of terms so have to retire this year. Waitaki Mayor Alex Familton has now officially lodged his nomination to seek a second term.
Mr Familton had already indicated he would be standing, and at this stage faces challenges from deputy mayor Gary Kircher and Oamaru man Bruce Cawley, who is making his fourth attempt at the mayoralty but his first as a councillor for the Oamaru ward.
Wanaka's Lyal Cocks yesterday announced he will not seek the Queenstown Lakes mayoralty, focusing instead on running for a second council term representing the Wanaka ward.
Despite giving some "serious consideration" to a tilt at the mayoralty, a continuing involvement with the Queenstown Lakes District Council's big-ticket projects in Wanaka would be better served in a councillor's seat, he said.
