Sadie was born in Cape Town, South Africa and now lives in London, England. Sadie has been acting since she was 10. Sadie's first role was as the voice of Phoebe in 47 episodes of the cartoon "Pop Paper City". The cartoon aired in the UK from 2022. Sadie also plays the role of Wendy Lancaster in the Apple TV production "Constellation", which aired internationally from 2024.