In the film directed by Tom Hooper, Hathaway plays a young mother, Fantine, who loses her job in a factory and struggles to find money to support her daughter. The film is based on the musical of the same name by Alain Boublil and Claude-Michel Schonberg, which in turn based on Les Miserables, the 1862 French novel by Victor Hugo.
Along with Hathaway, other actresses vying for the golden statuette were Amy Adams ("The Master"), Sally Field ("Lincoln"), Helen Hunt ("The Sessions") and Jacki Weaver ("Silver Linings Playbook").
The actress got emotional as she gave her acceptance speech, thanking family, and the film's cast and crew.
Hathaway had also won the Golden Globe and BAFTA award in the same category earlier.