[4][5] Prior to acting, she took up ballet to help her coordination after a dyspraxia diagnosis and attended Tring Park School for the Performing Arts in Hertfordshire.
[8][9] Bartlett landed her first major role in The Passing Bells, a 2014 BBC One World War I television drama.
[11] She played the recurring roles of Sophia and Keren Smith in Da Vinci's Demons[12][13] and Poldark respectively.
[4] In 2016, Bartlett appeared in the sixth season finale of the HBO series Game of Thrones, "The Winds of Winter" as a member of House Frey, then revealed to be Arya Stark in disguise.
[21] It was later revealed that Bartlett lodged a formal complaint against co-star Tok Stephen, but it was not upheld, leading to her departure.