In 2018 and 2019, Johnston-Green played for the
Newcastle Knights in the
Tarsha Gale Cup, captaining the side in 2019. On 15 February 2019, she started at for the
Indigenous All Stars in their 4–8 loss to the Maori All Stars. On 21 June 2019, she started at for New South Wales under-18 in their 24–4 win over Queensland in the first ever Women's under-18 Origin game. She scored a try and was named Player of the Match. In July 2019, Johnston-Green joined the
Sydney Roosters NRL Women's Premiership team. In Round 1 of the
2019 NRL Women's season, she made her debut for the Roosters in their 12–16 loss to the
New Zealand Warriors. On 11 October 2019, she started at for the
Prime Minister's XIII in their 22–14 win over the Fiji Prime Minister's XIII. On 25 October 2019, she was named 18th player for
Australia for their Test match against
New Zealand. On 22 February 2020, she started at for the Indigenous All Stars in their 10–4 win over the Maori All Stars. In March 2020, Johnston-Green joined the
Central Coast Roosters NSWRL Women's Premiership team. Johnston-Green suffered a knee injury while playing for the Central Coast and was ruled out of the
2020 NRL Women's season. On 20 February 2021, she represented the
Indigenous All Stars in their 24–0 loss to the
Māori All Stars. On 1 July 2021, Johnston-Green was announced as the
Newcastle Knights' first ever NRLW signing. In February 2022, she was announced as one of the club captains. In round 1 of the delayed
2021 NRL Women's season, Johnston-Green made her club debut for the Knights against the
Parramatta Eels. In late September 2022, Johnston-Green was named in the
Dream Team announced by the
Rugby League Players Association. The team was selected by the players, who each cast one vote for each position. On 2 October 2022, Johnston-Green played in the Knights' 32-12
NRLW Grand Final win over the
Parramatta Eels. In 2023, Johnston-Green played at in the Knights' 24-18 Grand Final win over the
Gold Coast Titans. In May 2024, Johnston-Green signed a 3-year contract with the
Cronulla-Sutherland Sharks, starting in 2025. ==References==