"It was so out of the blue that I wasn't even sure whether I should accept it," she said. "I was in that sort of space and talked to a very close confidant, talked it through and, at the end of the day, it's such a special thing so I decided that yes was the right answer.
"It was a huge surprise and I feel very honoured to be part of a special group of New Zealanders."
Castle already established herself inside a special group of administrators when, in 2013, she was named as the new boss of the Bulldogs. Rugby league's last female CEO was in 1998 and the NRL, often a bastion of masculinity, has seen only three women in charge of clubs during its history.
While her appointment drew understandable headlines, Castle initially thought little of the role gender had to play. But, after learning of her influence on other women forging careers in sport, she now ranks that broken barrier as one of her proudest achievements.
"I didn't really think anything of it. I just thought it was the right thing to do and it was a job that I had aspired to do over a long period of time.
"But the reaction from other females across Australia and New Zealand has been really overwhelming - how inspirational they see it and how it's maybe broken down a bit of that glass ceiling for something that other females can do in the future."
A man who focuses on breaking down mental barriers was also appointed an officer of the Order of Merit. Gary Hermansson has been to eight consecutive Olympic and Commonwealth Games as the Kiwi team's sport psychologist, starting the role at Kuala Lumpur in the infancy of the discipline.
Hermansson has helped sport psychology become accepted as a potential difference-maker in elite sport but, at 73, this year's Glasgow Games were likely his last hurrah.
Inline speed-skating coach Bill Begg earned the same honour as Castle and Hermansson, and former sporting boss Chris Moller was appointed a companion of the Order of Merit.
Moller was chief executive of the NZRU when New Zealand won the rights to host the 2011 Rugby World Cup, going on to enjoy a stint as chairman of New Zealand Cricket.
Appointed as members of the Order were Bruce Anstey (services to motorsport), Scott Carter (services to sport), Emmet O'Sullivan (services to polo), Tom Pryde (services to sport and the community), Ivan Vicelich (services to football) and Stewart Wilson (services to cricket). NZME.