Born in Washington, D.C., Weigert earned her bachelor's degree from Brandeis University before moving on to her master's in drama from New York University. After graduating, she built up an impressive body of stage work, including playing Poppy Norton-Taylor in a Broadway revival of "Noises Off" (2001). Weigert advanced her career with a starring role in a production of Richard Nelson's "Madame Neville" (2001), which also featured Joely Richardson and Macaulay Culkin. The performance earned the actress nominations for both a Drama Desk and Lucille Lorte award. Also that year, Weigert played Masha in the popular Central Park-staged production of Anton Chekhov's "The Seagull" (2001), directed by Mike Nichols and starring Meryl Streep and Kevin Kline. By this time, she had segued over to the screen, landing guest appearances on "Law & Order" (NBC, 1990-2010), "Without a Trace" (CBS, 2002-09) and "NYPD Blue" (ABC, 1993-2005). Meanwhile, director Mike Nichols was so impressed with her work in "The Seagull" that he cast her as Mormon Mother in the highly acclaimed miniseries "Angels in America" (HBO, 2003), which wove together numerous stories about people struggling with AIDS.Weigert also began making strides in features with a role in the festival-bound drama, "The Sleepy Time Gal" (2002), the romantic comedy "Two Weeks Notice" (2002) with Hugh Grant and Sandra Bullock, and the straight-to-video "What I Came For" (2004). But it was her being cast in "Deadwood" that helped propel her career to a new level and introduced her to a wider audience. As the foulmouthed Calamity Jane, who spent the show's three seasons drowning herself in whiskey while mourning the sudden death of her idol, Wild Bill Hickock (Keith Carradine), Weigert quickly became a favorite among fans and critics alike, most of whom recognized that her drunken bravado and threats of violence were a shield protecting a much softer, wounded interior. For her electrifying, nuanced performance, Weigert earned an Emmy Award nomination for Best Supporting Actress in a Drama Series in 2004. Meanwhile, she was cast by director Steven Soderbergh in "The Good German" (2006), which followed an American correspondent (George Clooney) who returns to Berlin soon after Hitler's defeat, only to stumble upon a murder mystery involving an American soldier.While continuing her acclaimed role on "Deadwood," Weigert made more frequent guest appearances on shows like "CSI: Crime Scene Investigation" (CBS, 2000-15), "Cold Case" (CBS, 2003-2010) and "Judging Amy" (CBS, 1999-2005). She also landed a recurring arc on "Lost" (ABC, 2004-2010), playing the cancer-stricken sister of Juliet Burke (Elizabeth Mitchell), only to see her role on "Deadwood" come to an end in 2006 when series creator David Milch and HBO failed to reach an agreement on how to continue the show. Though there was talk of making two two-hour movies to wrap out the series, the show seemed like it was permanently finished despite persistent hope among fans and occasional comments from Milch. Meanwhile, Weigert maintained an upward trajectory with episodes of "Law & Order: Special Victims Unit" (NBC, 1999-), "Life" (NBC, 2007-09) and "Numb3rs" (CBS, 2005-2010), while making occasional forays into features like the psychological drama "Things We Lost in the Fire" (2007), starring Halle Berry and Benicio Del Toro. Weigert also landed a role as the Adult Olive in "Synecdoche, New York" (2008), while maintaining a steady small screen presence on "The Mentalist" (CBS, 2008-15), "The United States of Tara" (Showtime, 2009-11) and "Miami Medical" (CBS, 2010).