The star, who landed a Golden Globe for her performance in the movie musical earlier this month (Jan13), beat Sally Field (Lincoln), Helen Hunt (The Sessions), Nicole Kidman (The Paperboy) and Dame Maggie Smith (The Best Exotic Marigold Hotel) to take home the Outstanding Performance by a Female Actor in a Supporting Role.
As she accepted the award, Hathaway paid tribute to the cast of her two big films of 2012, The Dark Knight Rises and Les Miserables, telling the audience: "I just want to thank my casts, because I've been in two great casts this year - The Dark Knight Rises and Les Miserables and I feel like as an actor, what you learn from one job, you use in the next, and I learned so much from The Dark Knight that I used in Les Mis. Thank you, you guys."
Meanwhile, Tommy Lee Jones celebrated an early victory for the male equivalent for his role in historical epic Lincoln, triumphing over Alan Arkin (Argo), Javier Bardem (Skyfall), Robert De Niro (Silver Linings Playbook) and Philip Seymour Hoffman (The Master).
Jones was not present to receive his award, so presenter Kidman accepted it on his behalf.
The 19th Annual SAG Awards are taking place at the Shrine Auditorium in Los Angeles.