He is in his last term with the health board, which currently has the best balance sheet in the country.
Before retiring as financial director of the Hawke's Bay Rugby Football Union he delivered 17 consecutive surpluses and with Unison profits also continued.
"I would have completed 19 years in July - it is quite unusual to do that length of time with a single organisation."
Getting Unison to a sustainable level was a challenge in the earlier years, helped by the purchase of the Rotorua and Taupo line networks, he said.
Unison's acquisition of Auckland transformer manufacturer ETEL "continues to be a real opportunity". ETEL's acquisition of an Indonesian transformer company last year was performing better than anticipated, with a government contract doubled, and New Zealand's only other transformer manufacturer, ABB, is closing its New Plymouth plant.
"We need to watch what happens now, whether the Asian or Australian manufacturers see New Zealand as an opportunity," Mr Atkinson said.
Despite missing out on the contract to roll out the Government's broadband network Unison's "bold investment in fibre", was another highlight.
"It was principally to provide the network for our own infrastructure, which is world-leading."
Spark has committed to using Unison's network where available and the fibre-enabled "smart grid" would lower overheads for decades.
He said he was lucky to work under "three good chairmen" before taking the role himself and enjoyed quality directors appointed by the Hawke's Bay Power Consumers Trust, which owns Unison on behalf of Napier and Hastings consumers.
"It has been a thoroughly enjoyable period of my life."
But as one door closes another opens. In March he will chair New Zealand Health Partnerships, subject to ratification, which is a collaboration of the country's 20 health boards created to identify efficiencies and Mr Atkinson is considering running in this year's election for the Power Consumers Trust because experienced hands John Newland and Arch Buntain are mandatorily standing down after nine years.
He has been approached to run as Hastings mayor but said the role deserved a commitment of six years, which he was unsure of making.
"I could consider running for council, but we need to see what time brings over the next nine or ten months."