"Having returned a couple of years ago I have a desire to put something back into Hawke's Bay."
Given his career in sport administration, he said he had the nous "to improve the lot of stakeholders across all levels of the rugby family in Hawke's Bay".
"I was a very average [Lindisfarne] first XV halfback," he said with a laugh.
Born and raised on a farm outside Dannevirke, rugby was an integral part of his childhood.
"While not reaching any great heights as a player the clear highlight was winning the Ross Shield with Dannevirke in Taupo in 1982, amazingly as a halfback," he said.
The Otago University graduate had embarked on a career in sales and marketing for breweries Carlton United and Lion as well as working in thoroughbred racing administration. He spent 11 years (2004- 2015) as director of racing at NZ's largest club, the ARC based at Ellerslie.
While there he was pivotal in establishing the Karaka Million race night, a joint venture with New Zealand Bloodstock.
"We also introduced twilight racing to Ellerslie where live bands were central to the success of these themed events," he said.
Castles assumed the mantle of Hawke's Bay Racing chief executive in August 2015.
"The clear highlight of my time here is returning a cash surplus on operations for the first time since 2012 in the 2016-17 season."
He put it down to the careful management of costs and improved and diverse revenue streams for the fiscal fillip.
The Poverty Bay Turf Club, the Waipukurau Jockey Club and the Wairoa Racing Club also engage Hawke's Bay Racing to provide raceday management.
"Many of the challenges faced by these smaller country clubs mirror those encountered in the rugby environment," he said.
Castles said the skills in governance, marketing and promotion, human resources and media were strengths he would bring to the table.
His appointment to the board of Sport Hawke's Bay recently endorsed that claim, he said.
"I don't profess to have the answers to all of Hawke's Bay rugby's issues but I am prepared to listen to, debate with and then represent the views of the wider rugby fraternity.
"While I see it as vital to have a strong Magpies team as the figurehead of rugby in this proud province, I believe it incumbent on the administration to make sure rugby at all levels is given the resources and opportunity to grow and prosper.
"My undertaking is that I will bring a common sense approach and can-do attitude to the issues facing rugby from Wairoa through to Dannevirke," said Castles, considering it a privilege to represent the clubs of this province at board level if elected.