Away from ER she has acted mainly on television, but she has also played various parts in films. Stringfield has famously left several major roles on successful television programs at the height of their popularity, which has led to her being nicknamed "The Goodbye Girl" in Hollywood.
She developed a penchant for acting while attending Klein High School, where she starred in various musicals and plays including Oklahoma, Mother Courage, and Fiddler on the Roof. At the age of 18 she attended the Acting Conservatory of SUNY at Purchase — rooming with fellow actress and student, Parker Posey. During this time, she appeared in numerous off-Broadway productions and she tamed her Texan accent with the help of a college speech teacher. Stringfield graduated in 1989 with a Bachelor's degree in Fine Arts.
In order to be released from her contract, Stringfield was forced to sign a no-work agreement, which blocked her from working on television for the remainder of her original contract. Stringfield's decision to quit reportedly angered the show's executive producer, John Wells, because she left just as Dr. Lewis got embroiled in a budding romance with Anthony Edwards' Dr. Mark Greene. Stringfield has commented: "I wouldn't describe the situation as pleasant. The producers were in shock. They tried to talk me out of it. It took a long time to get out of my contract."
Stringfield's much publicised departure reportedly "sent a small shock wave through Hollywood and her exit episode in November 1996 attracted 37 million viewers, the biggest night of the season for the NBC network. Stringfield quit just as television executive Dick Robertson was closing a deal that guaranteed the ER cast millions in future earnings from sales to cable and syndication, meaning she effectively "walked away from a fortune.
Stringfield claims she was asked to reprise the role of Susan Lewis in ER several times, but turned each offer down. However, following the birth of her first baby, she approached the producers of ER and then rejoined the cast in 2001, the show's eighth season. "I changed my mind," Stringfield commented, "I really want to work now. It just made sense for me to go back to ER. 26.7 million people watched Stringfield's return, placing the show at first place in the ratings and displacing the hugely popular Friends from the top spot.
During her second stint in ER, Stringfield's character was featured in a special 'crossover' with NBC's New York based police drama, Third Watch, which aired in 2002. She remained in the role for four additional seasons, however in August 2005 Stringfield announced that she would be leaving the show again as the 12th season came underway. "I am extremely grateful for the time I spent on ER," Stringfield explained. "It is a wonderful show, and there are so many people I will miss. But I'm ready for new roles and new challenges.
In 2007, Stringfield guest starred as attorney Nora March in the CBS drama, Shark. She also played a recurring role in the HBO drama Tell Me You Love Me (previously known as "Sexlife"), which also aired in 2007. In 2008, she filmed for the film The Stepfather, a remake of the 1987 American thriller film of the same name. Most recently she appeared in an episode of the USA Network drama In Plain Sight.
In addition to acting, Stringfield has also done voice-over work, which has included providing the voice of Eyeleen in the children's television show Blue's Clues and voicing her ER character for the PC game, ER: The Game. Stringfield was also featured in the U.S. Got Milk? advertising campaign, despite being lactose intolerant.
In 1996 she won a Q Award for "Best Actress in a Quality Drama Series" and in 1997 she, along with several of her ER cast-mates, won a Screen Actors Guild Award for "Outstanding Performance by an Ensemble in a Drama Series". In addition Stringfield was voted one of the "List of FHM 100 Sexiest Women|100 Sexiest Women in the World" by readers of FHM Magazine in 1997.
Stringfield dated the investment banker Odell Lambroza, and it was widely reported that Lambroza was the reason she quit ER in Oct 1995, in order to move to New York with him . The couple split just one year later in August 1997, reportedly due to objections from Lambroza's family — Orthodox Jews, who were against their sons's engagement to a Christian and wanted Stringfield to convert to Judaism, which she refused to do. However, Stringfield claims the break-up was amicable and denies that it was religion related.
Stringfield went on to marry the journalist Lawrence Joseph in October 1998. Stringfield and Joseph divorced in January 2006 after 7 years of marriage. They have two children together: daughter Phoebe, born in March 2001; and son Milo, born April 12 2004. Stringfield currently resides in Los Angeles.