She took a gap year between school and university to work on the film Children of Men (2006). In 2018, she starred in the Netflix Original crime drama series Seven Seconds.
Ashitey was born in Enfield to Tina, a medical secretary, and Paul, a dentist, who are both from Ghana, and has an older sister (Grace, who studied at the University of Warwick), and an older brother. Ashitey attended Brimsdown primary school in Brimsdown, Enfield before being educated at The Latymer school in Edmonton, North London. She graduated in anthropology from the School of Oriental and African Studies in 2009.
