As first reported by the New Zealand Herald, the long-time New Zealand sport administrator replaces Peter Miskimmin, who announced in August he would be stepping down after 11 years.
Castle is believed to have got the nod over Katie Sadleir, a long-time sports administration insider and former Olympian. It's understood Sadleir and Castle were the only candidates granted a final interview.
The announcement comes just days after deputy prime minister Grant Robertson retained his portfolio as Minister of Sport and Recreation.
Castle is Sport NZ's third CEO after Miskimmin and Nick Hill, and the first woman to lead the crown agency.
She was CEO of Netball New Zealand from 2007 to 2013, before filling the same role from 2013-17 with the Canterbury-Bankstown Bulldogs - the first woman to be CEO of a club in the NRL.
Bulldogs officials revealed following her departure that the club couldn't be active in the transfer market until 2021 because players were offered back-ended contracts while Des Hasler was coach.
Castle also attracted criticism for her role in the club's handling of the salary cap along with Hasler and chairman Ray Dib, though said at the time she had a clear conscience.
Castle became boss of Rugby Australia in 2017, before leaving this year, after being told she no longer had the support of the RA board – a move some felt was a knee-jerk reaction.
She was, according to the then RA chairman Paul McLean, subjected to sustained bullying from "faceless people" while in the job. Many Australian sport commentators both celebrated her demise and suggested she was hung out to dry for the failings of others.
It ended a tumultuous era of Australian rugby, with Castle overseeing the Wallabies' quarter-final exit at last year's Rugby World Cup where her relationship with former coach Michael Cheika reportedly fell apart.
Castle has also been criticised for her handling of the Israel Folau legal battle and the dire situation the game finds itself in as it tries to find an interested TV partner for a broadcast deal beginning next year.
She also suffered the sting of having to announce in March that the game had recorded a loss of $9.4 million for 2019, according to a preliminary independent financial audit.
Castle has also held roles within SANZAR (Super Rugby and the Rugby Championship), the ANZ Championship netball competition and the International Netball Federation (INF).
Sport NZ chairman Bill Moran said that Castle "brings tremendous breadth and depth of experience as a CEO in sports administration and is a proven people and organisational leader. The Board of Sport NZ see her has the ideal person to lead our organisation forward as we continue our important work in addressing declining participation among young people and protecting the strength and integrity of our sector".
Castle, who was made an Officer of the New Zealand Order of Merit (ONZM) in 2015 for services to business and sport, added that she is joining Sport NZ "at a key moment in our sector's history. Covid-19 has had an enormous impact at all levels of the sector but with the Sport Recovery Package there is a once in a lifetime opportunity to solidify the sector and reshape it to be more robust and deliver more participation opportunities."
Castle will officially take over on December 15, at a time where the sector's in flux.
Participation has plummeted in many of the country's traditional team sports, particularly during teenage years, while the overheated and increasingly commoditised secondary sport sector is a nettle the organisation has failed to grasp.
A tall task for someone who's own role will surely be under the microscope.
