[4] She played junior football for Burleigh Heads as well as Robina City[5] and attended Palm Beach Currumbin State High School in her teenage years.

However, she was later ruled out for a significant amount of the season after suffering a deep cut to the leg in the carpark following a match in the 2013 AFC U-19 Women's Championship.

[9] Arnold was approached to switch codes and play Australian rules football in the newly formed AFL Women's in 2016, but chose to remain in soccer.

On 9 July 2020, Arnold signed for English club West Ham United of the FA Women's Super League where she has been the teams captain since 2023.

[13][14] On 18 April 2021, Arnold was handed a surprise 20-minute cameo in midfield during an 11–0 win over Chichester & Selsey in the fourth round of the Women's FA Cup.

[18] She made her debut in November that year, keeping a clean sheet in a win over Chinese Taipei in the 2013 EAFF Women's East Asian Cup preliminary round 2.

[19] She soon began to feature regularly in national squads in 2013, with previous incumbent goalkeepers Melissa Barbieri and Lydia Williams unavailable.