Graduated from Brandeis University (Waltham, Massachusetts, USA).
Following undergraduate training, went on to earn Master's degree in drama from New York University.
Engaged to Daniel Zelman. 
Is severely allergic to flowers and perfumes.
Was named one of the 50 Most Beautiful People by People Magazine in 2002.
Named TV Guide's "best dressed woman" in 2003
Was Rhode Island's Junior Miss in 1986.
Gave birth to a son, Roman Walker Zelman, in Los Angeles, weighing 5lbs 14oz. [April 7, 2004]
Beat Nicollette Sheridan for the role of Grace Adler in Will & Grace at the final auditions
Although her son Roman is not deaf, she has taught him a few words in sign language to make communication easier for him until he's more able to talk.
Like her character in "Will & Grace", she comes from a New York-based Jewish family.
Appeared with her "Will & Grace" (1998) co-star Shelley Morrison in an episode of "Prey" (1998): "Revelations". While Messing was a steady member of the cast, Morrison only had a guest-starring role.
She has owned 3 mansions in Hyde Park, Piccadilly Circus, and Belgravia in London, England since January 1, 1986.