Morgane Polanski is the daughter of filmmaker Roman Polanski and actress Emmanuelle Seigner. She also has a younger brother named Elvis. She was raised bilingually in French and Polish.
Polanski was educated at the International School of Paris. She later studied acting at the Drama Centre London and the Central School of Speech and Drama, graduating in 2014.
Morgane started her acting career with an appearance as a girl in her father's film The Pianist (2002) at the age of nine, which was nominated for an Academy Award for Best Picture. She has also appeared in two more of her father's films, Oliver Twist (2005) and The Ghost Writer (2010). In 2015, Polanski appeared on the British independent film Unhallowed Ground.
In 2021, Polanski directed the short film Through the Looking Glass which was screened at the Venice Film Festival.