Hosseini made her acting debut in 2009 at the age of nine, when she starred as daughter of main characters in Asghar Farhadi's Oscar-winning film A Separation (2011). She won the Silver Bear for Best Actress at the 61st Berlin International Film Festival jointly with Leila Hatami, Sareh Bayat, and Sarina Farhadi as an ensemble for A Separation.
- "Kimia Hosseini Booklet with Bodyguard Actors". Salamcinama. Retrieved 19 February 2011.
- Brooks, Brian (2011-02-19). "Iran's "Separation" Wins Berlinale's Golden Bear". IndieWire. Retrieved 19 February 2011.