The actress made a guest appearance on the CBS drama in 2011 as Viola, a top lawyer who "brims with power and self-confidence", and reprised the part earlier this year.
In an interview with Parade, Wilson admitted that she had grown tired of playing the same types of characters and found it refreshing to sink her teeth into something new.
"You have no idea! That's why I took the role. I've played so many mums, best friends, sisters and understanding people," she explained.
"I said, 'Is there nobody out there I can play who's kind of cranky?' About a week later, The Good Wife came up, and I was like, 'I'm in!'"
In January, it was announced that The Big C star Nadia Dajani would join the Good Wife cast.
Parker Posey, Dennis O'Hare and Amy Sedaris have also returned to the show to further their characters' storylines.