Diggs will play Dean Levine-Wilkins, a meticulous and talented partner at Lockhart/Gardner who decides to join Diane (Christine Baranski) and accompany her to Florrick/Agos, the firm started by Alicia (Julianna Margulies) and Cary (Matt Czuchry).
"We couldn't be more excited to have Taye on the show," executive producers Robert and Michelle King said in a statement. "We've been huge fans for years, and love his ability to play comedy and drama with equal ease."
Diggs, who currently stars on TNT's Murder in the First, is slated for multiple episodes.
The Good Wife returns on Sunday, Sept. 21 at 9/8c on CBS.
(Full disclosure: TVGuide.com is owned by CBS.)
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