She began playing rugby at the age of four with her brother in a Timaru Harlequins Rugby Football Club boys’ team. In 2015 she was captain of the Timaru Harlequins Rugby Football Club's under 12 team and was one of only two girls to make the South Island under 48 kg side. She was a member of every South Canterbury age group rugby team until at the age of 13 she became ineligible to play mixed rugby and switched from playing for Harlequins to playing only for Timaru Girls' High School team and regional girls teams. In 2017 Miller played for Timaru Girl's High School in the fifteen-a-side Aoraki secondary schoolgirls competition. The team lost 60–42 to a combined Mt Hutt-Ashburton college in the final despite Miller scoring three tries. Alongside the Te Moananui triplets, Miller (who by now had acquired the nickname "Scooter") was a member of the Hanan Shield secondary schoolgirls rugby team which competed at the South Island secondary schoolgirls rugby tournament at Christchurch in 2017. The youngest player at the event she was named the most valuable player and captain of the tournament team. Until she moved to Christchurch Miller mainly played the fifteen-a-side rugby as an open-side flanker with only occasional games of sevens, such as a game in 2018 for South Canterbury against Mid-Canterbury at a girl's under-15 sevens tournament. They then attended the Amsterdam International Quadrangular under-18 girls' tournament in the Netherlands they played against the Nemos, who were the Dutch club champions and the national U18 teams of Sweden and the Netherlands. The team won all their group games on the first day in Amstelveen, before at the second date of competition at the National Rugby Centre in Amsterdam beating Holland 26–17 and the Nemos 47–0 in the semi-finals despite losing two members of the team to injuries. They then beat Holland in the final, 26–10.
Condor competition In 2019 she was a member of the Christchurch Girl's High team that won the National Condor Sevens title. In the semi-final against reigning championships Hamilton Girls’ High School Miller after earlier being sin-binned scored the winning try in extra time following an 80 metres sprint to the line. In the final she scored four tries in her team's 29–14 win over Howick College from Auckland. While the Christchurch Girl's High team only came fifth at the 2020 National Condors Girls Tournament, Miller was selected for the 2020 Condor New Zealand Secondary School Girls team. Playing against NZ Barbarians, Niue Fiti Poua, Cook Islands, New Zealand Maori, New Zealand Cavaliers and New Zealand Fijians the team won of their games. By 2019 Miller had come to the conclusion that she preferred to play the more open style of sevens over the fifteen-a-side game. In 2021, Miller was called to attend a High Performance Development Camp.
Farah Palmer Cup She played for
Canterbury in the
Farah Palmer Cup competition
Black Ferns sevens Miller signed a contract to join the
Black Ferns Sevens squad in 2022. Miller was a member of the Black Ferns Sevens team that competed in the
2022–23 World Rugby Women's Sevens Series. She played in all of the season's games and was named in four separate tournament dream teams, named player of the final at the Sydney tournament and at the end of the season was named Rookie of the Year by World Rugby. In November 2023 Miller signed a four-year contract with New Zealand Rugby which committed her to playing for the New Zealand Women Sevens team through to 2027. At the time it was the longest contract signed by a New Zealand rugby woman player. Miller scored three tries over the course of the
Olympic sevens competition and won a gold medal after the New Zealand team triumphed against Canada in the final, 19–12. She was New Zealand's youngest female gold medallist at the Paris Olympics.
Black Ferns fifteens Miller made her international debut for the
Black Ferns in their 79–14 win over the
USA Eagles in the
Pacific Four Series on 24 May 2025. In July 2025, she was named in the Black Ferns side to the
Women's Rugby World Cup in
England. Miller made six appearances at the World Cup, scoring a total of four tries, two of which were against Spain and the other two against Japan.
Return to sevens Following the completion of her duties with the fifteen-a-side team Miller returned to compete in the sevens team in the 2025-26 sevens series. The game against Japan in pool play at the
Vancouver tournament held on 7–8 March 2026 Miller score her 100th sevens try. It had taken her 27 tournaments, putting her third in New Zealand rankings behind Porta Woodman and Michaela Brake who had both taken 15 tournament to reach the same milestone. In the final of the same tournament Miller scored a try which bought her total number of tries in Sevens finals to 17, behind Michaela Blyde (38), Portia Woodman (34), Maddison Levi (18) and ahead of Stacey Waaka (14). ==Awards and honours==