Following minor roles in independent and short films, Mackey had her breakthrough playing Maeve Wiley on the Netflix comedy-drama series Sex Education (2019–present)
She has appeared in the drama film Eiffel (2021) and the mystery film Death on the Nile (2022).
Mackey was cast in her first professional role with the Netflix comedy-drama series Sex Education as Maeve Wiley
In 2021, Mackey led the independent romantic drama film Eiffel,[19] which premiered at the Alliance Française French Film Festival and has earned numerous international theatrical release
In May 2020, it was announced that Mackey would portray the novelist Emily Brontë in the upcoming biographical film Emily
she was cast in the Warner Bros film Barbie (2023), which is directed by Greta Gerwig and will additionally star Margot Robbie, Ryan Gosling, Simu Liu, Will Ferrell and Sex Education co-stars Ncuti Gatwa and Connor Swindells.