[11] In a 2013 interview, she said, "I would say if I had a religion, it would be gratitude…I love the tradition of Judaism that on Friday nights, Shabbat means 'Goodbye to the workweek; hello to family and the weekend.

She is from New York City, but she moved with her mother to different countries and states throughout her youth, including Sussex, England, and Paris, France.

[13] She graduated with a degree in art history and English from Sarah Lawrence College, where she appeared in several campus plays.

In 1994, Margulies was cast in the pilot episode of the NBC medical drama ER as Carol Hathaway, an emergency care nurse who attempts suicide.

Her character was originally intended to die; however, test audiences overwhelmingly wanted her to survive, so the producers changed the plot.

[17] Then-unknown actor George Clooney, who had filmed the pilot episode with Margulies, called her to let her know that he had overheard producers saying that her character might become a series regular.

[20] In 2021, she explained in her memoir, Sunshine Girl, that she had been feeling homesick for New York after spending six years filming the show in Los Angeles.

She wanted to return to theatre and take on a leading role in The Mists of Avalon, a miniseries based on the 1983 fantasy novel of the same name, which she had loved as a child.

[20] In a New York Times interview with Bill Carter, Margulies shared that another factor in her decision was a desire to protect her ER character, Carol Hathaway, from certain story changes that were happening as the show continued on into later years.

It started to become very clear to me that without George, my character was just going to be the liaison to flashy sort of bits of things instead of one fluent, cognizant thought and I felt sad about it.

"[21] Had Margulies accepted the $27 million contract for a seventh and eighth year of ER, it would have made her one of the highest paid women on television.

"[23] In February 2000, Margulies hosted an episode of the NBC late-night sketch series Saturday Night Live.

Her work after ER included the 2002 films Evelyn, with Pierce Brosnan, and Ghost Ship, with Gabriel Byrne and Ron Eldard.

She starred as Morgaine, the protagonist and narrator of the TNT miniseries The Mists of Avalon (2001) and participated in the documentary film Searching for Debra Winger (2002).

In 2004, she guest-starred in a two-episode arc in season four of the hit NBC comedy series Scrubs as Neena Broderick, an unscrupulous lawyer who sues Turk and has a brief sexual relationship with J.D.

In April 2006, she appeared in four episodes of the sixth season of the HBO crime drama series The Sopranos, portraying realtor Julianna Skiff.

In August 2006, she appeared alongside Samuel L. Jackson in the action film Snakes on a Plane, as flight attendant Claire Miller.

In an August 2006 interview with tvguide.com, Margulies said she was close to accepting an offer to return to ER for a four-episode arc, with Noah Wyle, that filmed in Hawaii during the 2005/06 season.

"I left on very good terms with [ER exec producer] John Wells, and every year they ask me back and I love that they do," she told TV Guide in 2006.

In 2009, after returning to ER for one episode during its 15th and final season, Margulies began starring in the CBS legal drama series The Good Wife.

Reflecting on her roles as Alicia on The Good Wife and as Carol on ER, Margulies told Entertainment Weekly in 2021, "I have gotten to play two of the richest, I think, female characters on television.

"[28] In a 2019 interview for the Series Mania Festival, Margulies said that "it's tied between Carol Hathaway and Alicia Florrick" when it comes to the role she is most proud of having played.

[5] In 2018, Margulies co-starred in the dark comedy series Dietland on AMC, which was cancelled after one season despite positive reviews.

Titled Three Magic Balloons, the story is based on one that the actress's father, Paul Margulies, wrote for her and her sisters.

[38] In October 2020, Margulies announced on her Instagram that she was writing an autobiography, Sunshine Girl: An Unexpected Life, published by Ballantine Books.

[55][56] In January 2024, she signed an open letter calling on the Academy of Motion Picture Arts and Sciences to include Jews in its representation and inclusion standards.

[57][58] In 2023, Margulies faced backlash from comments she made in a discussion of antisemitism and the Israel–Hamas conflict on The Back Room with Andy Ostroy podcast.

I want to be 100% clear: Racism, homophobia, sexism, or any prejudice against anyone's personal beliefs or identity are abhorrent to me, full stop.