Pryles has left the organisation to be the chief executive for Hockey Australia. 

Williams was previously managing director of the Rugby Football Union for Women in England, and worked as the Rugby Football Union's head of delivery.

This included helping to organise the Women’s Rugby World Cup in England in 2010, before Williams established her own consultancy firm.

"Rosie is an exceptional leader with a track record to match," declared Softball Australia chair Richard Lindell.

"She has a deep understanding of the dynamics and drivers of sport, and a proven ability to bring all stakeholders on a journey to deliver the outcomes we’re all striving for in participation and high performance - with a laser focus on member value and experience, along with the athlete journey.

"We're at a really exciting point for softball as we build on the work of recent years and start to formulate our next strategic plan so it's fantastic to have Rosie with us as we prepare for our next phase."

Williams, who was given the Order of the British Empire honour in 2013 for her contribution to women's rugby union, will assume Softball Australia's chief executive post in late February.

National operations manager Bron Parry is acting as chief executive in the interim.

"I'm thrilled to be returning home to join the team at Softball Australia," Williams said. 

"It's a sport I've always loved having played a lot at school and university, and I think it has great potential for growth and high-performance success in both the women’s and men’s programs in Australian and international competition.

"What excited me the most is seeing the impact that the game of Softball has on young people and how it has the ability to unite people from many different backgrounds."

Australia's women's team placed fifth in the softball competition at the Tokyo 2020 Olympics.