Louis Canning is an attorney from New York with his own law firm, Canning & Meyers. He suffers from tardive dyskinesia, a condition which causes erratic body movements. He often uses this to his client's advantage in court, attempting to endear himself and win sympathy from the judge and jury.
Canning's motivations are often mysterious, with both Diane and Alicia repeatedly seeking to understand just what he wants from them. Although generally humorous and affable, Canning is a ruthless lawyer and businessman.
He has squared off with Alicia Florrick on various occasions, and been known to use trickery in his cases. Shortly after buying the late Jonas Stern's firm, he offered Alicia a job with full partnership, which she rejected.
In season five, Canning merges with Lockhart/Gardner after Will's death. David Lee made the bargain to prevent Diane from merging with Alicia. Canning effectively takes over Will's office, causing some tension, especially in season 5 episode 18, "All Tapped Out," when he remarks to Kalinda, "I'm the New Will."
Canning reveals to Diane (and Kalinda later corroborates), that he is dying, also claiming that he "wants a home," and this is why he has chosen to come to Lockhart/Gardner. Canning's intentions are only partially true. Despite his claims of cooperation, he and Lee conspire to not only push Diane out, but to steal clients from and bankrupt Florrick/Agos. Later, he approaches Alicia when she decides to open her own firm with an offer to be her partner.
In season six, Canning spent multiple episodes in the hospital dealing with his kidney failure. In that time, a more compassionate side of Canning was shown as he wanted to give a substantial amount of money to the family of the girl whose kidney he had received. However, it was later revealed that this was a plot with David Lee to make Alicia look bad during her run for State's Attorney as the family wanted the money to go to a questionable charity. Canning returned in an anger-filled tone in the season finale ("Wanna Partner?") after finding out that Simone was fired from her paralegal job at Lockhart, Agos, & Lee because Diane, Cary, and David thought that she could be retaining important information and forwarding it to Louis. Later, he went to Alicia's apartment and delivered the final words of the episode, asking Alicia, once again, if she would want to partner with him.
- ''Poisoned Pill (9 November 2010)
- Real Deal (8 February 2011)
- Wrongful Termination (5 April 2011)
- Parenting Made Easy (4 December 2011)
- Gloves Come Off (18 March 2012)
- The Dream Team (29 April 2012)
- Boom De Yah Da (6 January 2013)
- The Seven Day Rule (27 January 2013)
- A Material World (13 April 2014)
- All Tapped Out (20 April 2014)
- The Deep Web (4 May 2014)
- The One Percent (11 May 2014)
- A Weird Year (18 May 2014)
- The Line (21 September 2014)
- Old Spice (26 October 2014)
- Red Zone (9 November 2014)
- Mind's Eye (8 March 2015)
- Open Source (15 March 2015)
- Wanna Partner? (10 May 2015)
- Bond (4 October 2015)
- Taxed (25 October 2015)
- Although generally distrusted, Canning can also be genuine and supportive, especially with clients.
- This is shown in "Open Source", as Canning (under the influence of anesthesia and tremor medication) wanted to liquidate and give his $18,000,000 from the stock market to the family of the girl whose kidney he received. However, it was later revealed that this was a plot with David Lee to make Alicia look bad during her run for State's Attorney as the family wanted the money to go to a questionable charity.
- He is married with two children.
- Canning was bumped to a season regular as of series six.
- It is revealed in "Wrongful Termination" that he is Jewish, as he was wearing a yarmulke at the funeral.
- It is revealed in "Mind's Eye" that he is dying of kidney failure. However, he received a kidney from a young girl when she died in "Open Source".
- This is the second time Michael J. Fox played a character, on television, that is known to be active in the stock market; the first being Alex Keaton in Family Ties.