David Lee is a named partner at Lockhart, Agos & Lee and former equity partner and the head of family law at Lockhart/Gardner. He is one of Chicago's most prominent divorce lawyers. Because of the fact that his sector brings in quite a lot of money for the firm, he thinks of himself as a very important contributor to the firm, and thus acts as if he is of a high position. When Alicia Florrick separated from her husband, she unofficially hired him to handle her children's trust and also to advise her about her options (financial and matrimonial) if she were to divorce Peter Florrick. He made it well known to all that he could not stand some of his coworkers; Julius Cain (equity partner and head of litigation), short time named partner Derrick Bond and Eli Gold (who ran his crisis management business out of Lockhart & Gardner and also an equity partner). David is a very outspoken person and is well despised for it.
Granted leeway and a degree of autonomy because of the large influx of cash he brings to the firm, David Lee is one of Lockhart/Gardner's most senior attorneys and is regularly seen chairing, or at least featuring prominently, in partnership meetings. He was responsible for coercing the management into offering fourth year associates partnership agreements in order to raise more capital, for rescinding those offers when the money was no longer needed, and was shown to be dismissive of the administrative staff when they rebelled due to low wages. In the fifth season he has become suspicious of the fourth year associates - believing, correctly, that they are planning to leave Lockhart/Gardner, and has begun investigating this.
Despite his apparent lack of emotion, he was visibly upset when Will died in season 5, rushing out of the partners' meeting and throwing associates out of a room to grieve. He later turned against Canning and joined Diane and Cary to form the law firm Lockhart Agos & Lee after Alicia becomes States Attorney.
Lee strongly disliked Bond as soon as he met him, and did not trust him for a minute. When Bond was removed from the firm, Lee did little to cover his happiness about it.
Lee and Canning have a good relationship, as Canning trusts him enough to manage his stocks in the stock market (as his Executor of Estate), which he has earned at least $18,000,000 as of "Open Source".