Preston has worked on numerous projects with her husband, actor Michael Emerson, whom she married in 1998.[4] Emerson played Ben Linus on television's Lost, and Preston was a guest star in episode 20 of season 3, "The Man Behind the Curtain" as Ben's mother Emily in flashback scenes, though she and Emerson never shared scenes together. The couple were featured in the 2004 comedy film Straight-Jacket and the 2008 feature film, Ready? OK!. She appeared in several episodes of Person of Interest as Grace Hendricks, the former fiancée of Emerson's character, Harold Finch.
On September 6, 2013, it was announced that Preston signed on to play a recurring character in the second season of the Kevin Bacon-led thriller, The Following. She portrayed Judy, a prostitute and ill-fated groupie of Joe Carroll. The show's second season premiered in January 2014.[8] Preston has appeared in a number of films as a supporting character. Including several critically acclaimed films such as Doubt and Duplicity, where she starred alongside stars such as Meryl Streep, Viola Davis, Clive Owen, and Julia Roberts.
In 2015, she landed a leading role on the short-lived NBC comedy series Crowded where she starred opposite Patrick Warburton, during which time she also appeared on the final season of The Good Wife for which she earned her second Primetime Emmy Award for Outstanding Guest Actress in a Drama Series nomination. Preston was originally slated for a four-episode arc, but due to commitments on her new show, she was able to appear only in one episode.
In August 2016, TNT announced that Preston had been cast in the drama-comedy Claws. Preston plays Polly Marks (Polly-Pol), a mild-mannered preppy with an "ankle bracelet" who recently served time in prison for identity theft.[9] The series was greenlit for a 10-episode first season.[10]
On December 16, 2016, CBS announced that Preston would reprise her role as Elsbeth Tascioni on The Good Wife spin-off The Good Fight.[11]
On January 31, 2023, CBS announced that it had ordered a pilot for a spin-off series, Elsbeth, in which Preston would reprise her role, though as the central character. It was ordered to series on May 9, 2023, and premiered on February 29, 2024. On April 18, 2024, CBS renewed the series for a second season.[12]