William Paul "Will" Truman was a named partner at Lockhart/Gardner and an old Boyfriend of Alicia Florrick.
Will and Alicia met when they were both in Law School at Georgetown; this connection allows Alicia to get a job as a Junior Associate at Lockhart/Gardner where Will is a named partner.
Will is shown to be a sports fan, often playing basketball with his friends or simply tossing a baseball around in his office. When the firm suffers financial troubles, a major sacrifice Will makes is to give up his season tickets for the games. Because of the same financial woes, Will and his collegue Diane Lockhart must decide who to hire between the two junior associates Alicia Florrick and Cary Agos.
In the early episodes of the first season, Will works with Alicia a lot. When Diane accuses him of favoring Alicia over Cary, he decides that he doesn't want to to have to fire any of the litigators. When he approaches Diane with this idea, he tells her that their fellow partner Jonas Stern costs them about as much as all of the other lawyers combined. Diane accuses him of wanting to take away the partner that votes with her. When fellow named partner Jonas Stern returns to the law firm hoping to represent himself after being charged with a DUI and battery, Will decides that this is an opportunity to push Stern out. He tries to get Alicia to tell him what she had discovered while representing Stern, but the information that Stern is suffering from dementia is protected by attorney/client privilege so Alicia can't tell Will. Stern decides his partners have betrayed him and quits the firm, taking his clients and a third of their business with him, determined to destroy the firm. This results in further financial difficulties for Diane and Will.
Will is shown to be a complex character. When Diane is approached by the Chief Justice to become a Judge and Will is the one person she tells, he celebrates the possibility of being the sole owner of their law firm if she leaves. However, Diane and Will are also shown to be each other's confidantes in Season 1. This changes in Season 2 when both decide to split the firm.
He is a loyal friend, shown especially in his relationship with Judge Baxter whom Alicia accuses of racism after one of her young clients is sent to a juvenile detention center. Will stringently defends his friend, until he makes the connection that Baxter has made a deal with the detention center to receive money from all those boys he sends there. He confronts Baxter and tells him he is going to jail.
While Will is clearly attracted to Alicia, he is also shown to be somewhat of a ladies man. He has various love affairs and when Alicia stands him up at dinner, he calls another woman. He also has several girlfriends throughout the series.