Ladj Ly began his career with the Kourtrajmé group. He first joined cinema as an actor, then as director with his first short film Montfermeil les bosquets (1997). Ly filmed his neighbourhood for a whole year and directed the documentary 365 days in Clichy-Montfermeil (2007) after the 2005 riots in Clichy-sous-Bois. He also directed 365 jours au Mali (2014) and the short film Les misérables (2017), awarded at the Clermont-Ferrand festival, then co-directed with Stéphane de Freitas the documentary À voix haute (2017). In 2019, he introduced his first feature film, Les misérables.