The "Vegas" star will play Colin, "a wild-eyed Irish attorney who has spent a decade successfully defending gang members and crime families. Now he’s looking for a home at a corporate law firm like Lockhart/Gardner where he clashes with the more conservative culture." Perhaps he could be lured away to join Alicia (Julianna Margulies) and Cary's (Matt Czuchry) new firm?
Other notable guest stars this season include Melissa George, Ben Rappaport, Jeffrey Tambor, Carrie Preston, America Ferrera and Gary Cole. Margulies has also teased the return of Michael J. Fox, Nathan Lane and Matthew Perry.
"The Good Wife" Season 5 premieres Sunday, Sept. 29 at 9 p.m. ET on CBS.