Chris Cooper
I know everybody talks about Streep and Roberts in this film but I thought Chris Cooper was outstanding in a supporting role here. I've always thought Cooper was excellent in pretty much anything he does - I know he's acclaimed within the business and amongst hardcore movie-fans, but his name doesn't always jump to people's minds when they're talking about the greatest actors that have been.
The scene where he tears into his wife over her treatment of Little Charles is the obvious stand-out but it's the other moments too - his awkwardness saying grace at the dinner table and, my favourite part, in Little Charles' first scene where he tells him how proud of him he is.
I sound like a total Chris Cooper fan-boy, but I really thought he was exceptional in this.