Buono will guest star on the CBS sitcom as "a woman who hires Lockhart Gardner after her husband dies on the job under questionable circumstances (and is being hustled to keep quiet)", reports TVLine.
Buono will make her appearance on this season's penultimate episode.
Earlier today, it was reported that Stockard Channing and Dallas Roberts will also reprise their roles on The Good Wife.
Buono has previously appeared on Mad Men, Castle and Hawaii Five-0.
The Good Wife airs on Sundays at 9pm ET on CBS.
Watch a clip of The Good Wife below: