He said highlights included working through the rates review, completion of the Carterton Events Centre building, the Wairarapa Governance Review Working Party report, and the 2013 Census results "that showed the Carterton district was the fastest growing council area in the North Island, at twice the growth rate of Auckland".
He was particularly proud to also have helped cement bonds between the council and Hurunui-o-Rangi Marae, which was "right and proper and long overdue".
"I leave the mayoralty with considerable sadness," he said.
"Working in council enables one to assist and serve people in a way that more directly impacts on them than is the case in central government, and it has been wonderful to be part of that," Mr Mark said.
"That said, it is clear to me that much of what councils are required to comply with and how they are able to serve their communities is dictated by central government, and it is my concerns around a raft of such matters that will affect the Carterton district that has led me to the decision that I should return to Parliament."
Mr Mark thanked councillors and their partners and spouses, "without whose support I know they would not be able to undertake the amount of work you do". After leaving the council chambers, he said the privilege of serving the people of Carterton as mayor had been brought into terrible focus after 11 people died in a hot air balloon crash at Clareville on January 7, 2012.
"The balloon tragedy, as horrific as it was, epitomised everything about Carterton that I cherish - the love, the compassion, the care."
His fiancee Christine Tracey, he said, had been "a rock supporting me in all facets of my duties as mayor and who stood firmly beside me during the balloon tragedy that so affected us all". Mr Mark, a former law and order spokesman for NZ First, said he had held up his hand as local government spokesman for the party, although roles were yet to be decided.
He told councillors there were significant differences between central and local government and he had learned much as mayor, which will "make me a better MP this time around than when I first entered Parliament in 1996".
"I always said it [mayoralty] was a golden job that can really make a difference in people's lives. But there are bigger issues out there and I can't fight them from here, I can't."