Preston will be back on the CBS drama for multiple episodes as kooky attorney Elsbeth Tascioni, reports TVLine.
Preston first appeared on The Good Wife in season three, where she acted opposite Julianna Margulies and Josh Charles.
Preston is also known for her role in True Blood as the redhead waitress Arlene Fowler, who has been part of the show since its debut in 2008.
"What I like about playing her is being able to ground her in some kind of truth while still honouring that humour and that thing that she represents," the actress previously said about her True Blood character.
"I love it that I'm responsible for serving up the humour on the show, but what has been wonderful for me is that the writers have also given me more dramatic things to deal with."
True Blood recently aired its fifth season, while season four of The Good Wife premieres on Sunday, September 30 at 9pm ET on CBS.
Watch a clip of The Good Wife below: