"I have known Raelene for a number of years, and have a huge regard for her and we are really looking forward to working with her."
Castle will take up her post on January 15, becoming the first female boss of any of the national governing bodies of the four major football codes in Australia.
But dismissing as "media fascination" her watershed leap into Australian rugby's hottest seat, Castle said "the work starts today" in reconnecting with disenchanted fans after one of the toughest years since the code went professional.
"The reality is sport has gender equity in it. There's people from both who are really delivering, particularly at grassroots level," said Castle, also a former Netball New Zealand chief.
"So I don't think it's enormous step to have a female chief executive. I'm excited about the opportunity.
"My experience in rugby league was very strong. I don't expect my experience in rugby union to be any different."
Castle spent four years at the Bulldogs, presiding over three NRL finals appearances for the club, including the 2014 grand final loss to South Sydney, before resigning this season.
"[The Bulldogs] really helped me understand the Australian sporting landscape. It's a unique landscape," she said.
"That experience working with the Bulldogs in that landscape and also working with a coach like Des Hasler, who's a strong personality, that will also help me when I have to forge a very strong relationship with [Wallabies coach] Michael Cheika."
The Wagga Wagga-born Kiwi's first priority is to "take a breath".
"It has been a very big year, it has been a challenging year, and this is about some stability moving forward," Castle said.
"But it's about building the relationships, building strong relationships with the states and the franchises and making sure we recognise that rugby is an important game right across the country and getting out and about and meeting some of the rugby people in the community.
"It genuinely is an exciting sport that has an international landscape that no other sport in Australia has.
"It offers something that the NRL and AFL can't offer and that is a genuine international and regular international platform for athletes to travel internationally to perform on the world stage."
RA chairman Cameron Clyne said Castle's commercial experience and ability to "make money" for the national body made her the standout applicant among more than 200 candidates, including former Wallabies captain and Fox Sports commentator Phil Kearns.
"Raelene is an extremely impressive executive who covered every base as far as what the board was looking for in a chief executive officer to lead our game into an important new chapter," Clyne said of the widely-expected appointment.
"But also Raelene is bringing a fresh set of eyes, but not new to this market."
