Season 5 takes place after Alicia joins Cary in opening a new firm. They take some of Lockhart/Gardner's (now known as LG) clients, but they need to survive under the fierce backlash of their ex-employers.

After winning the elections, Peter is now governor. Eli is his chief of staff and is having some problems with Marylin Garbanza, Director of the Governor's Ethics Commission. Meanwhile, the investigation of a ballot box, full of fake votes for Peter, may ruin his career. At the end of episode 15, Will Gardner is fatally shot in a courtroom by his client. This had a tremendous effect on many of the characters, particularly Alicia, Diane and Kalinda, all of whom reconsidered the course of their respective careers following his death. Finn Polmar was also introduced as a new ASA who befriends Alicia. Alicia decides to split up with Peter but will stay married in the public eye, as it benefits both of their careers. Louis Canning joins Lockhart Gardner as a partner and keeps Will's name on the letterhead, making the firm "Lockhart Gardner and Canning"; he and David Lee plot to kick Diane out of the firm. At the end of Season 5, Diane asks if she could join Florrick Agos with her $38 million in clients. Zach goes away to college and Eli asks Alicia if she would run for State's Attorney.