Meredith is the first ex-wife of Richard Castle and mother of Alexis Castle. Meredith and Rick were divorced when Alexis was a little girl; Rick found out Meredith was cheating on him when she served him with divorce papers and moved to California.
Castle describes her as a "deep fried Twinkie," that indulgence that's so bad for you that you only have it once a year, but having it every day would be ... eurgh.
She appears in episode 1.6 (Always Buy Retail) when she and Castle have one night of wild sex, and she announces that she is moving back to New York City to be close to him and Alexis. She eventually changes her mind when she fails to get an acting gig in the city, and instead finds work out of town.
Meredith is the antithesis to her very responsible daughter, as evidenced by her arrival at Alexis' high school, where she lies to the Head Master about there being a death in the family so she can pull the teenager out of class to take her shopping. She also makes a surprise visit to the precinct, and refers to Castle as "Kitten", causing repeated teases from Kate Beckett and her colleagues.
In Significant Others, Meredith invites herself to stay in Castle's loft while Alexis has mono, to "nurse her daughter back to health". Unfortunately, Kate is also staying at the loft while her apartment is being fumigated, and Castle is overwhelmed by conflicting females.
Meredith is portrayed by Darby Stanchfield.