Hesson's influence on the squad is often underestimated as the leadership of McCullum was more visible but it all starts at the top.
Before he took the reins, the New Zealand cricket side were perennial underachievers in all formats.
A few World Cup semifinal appearances belied the side's potential that would soon enough be realised with Hesson at the helm.
Hesson held a winning record in all three formats but the most impressive is his win-loss record in the ultimate game - tests.
In 55 matches under Hesson, New Zealand have won 21 compared to 19 losses.
For a team that, for the majority of their time in the international game, had shown far better ability in the shorter formats.
Is he New Zealand's greatest cricket coach? His record would definitely make you think so.
But what can't really be quantified is the change he's made behind the scenes and in the general attitude and style of the side.
A humble outfit with a highly regarded "no dickheads" policy is a long way from what the side was criticised for in years previous - 'prima donnas' and 'aloofness' were often used.
Hesson's departure has come a year out from the 2019 World Cup, which puts New Zealand in a difficult spot in terms of building towards the goal of going one better than in 2015 - arguably Hesson's finest achievement alongside a 13-match unbeaten streak in test cricket on home soil.
Under Kane Williamson's stewardship, New Zealand should be in good stead but a new leader needs to build on the foundations already set. There's no need for a rebuild a la 2013.
The obvious replacement would be former captain Stephen Fleming.
Since ending his career, Fleming has transitioned from probably New Zealand's finest skipper to a much sought after T20 coaching maestro.
A trio of IPL titles and a Champions League T20 title with Chennai Super Kings headline his coaching CV and would be a welcome sight to a cricketing public with increasing expectations of their home side.
But will he let go of the considerable pay that the IPL can offer unmatched? It remains to be seen.
Either way, for now we should appreciate the end of the most successful coaching era of New Zealand cricket.
As Kane Williamson said ...
"I've witnessed his work-ethic firsthand and have seen the sacrifices he's made, and I can only say I have the utmost respect for what he's achieved."