Weil was born in Passaic, New Jersey, to a family of actors. She was raised in, and continues to practice, Reform Judaism. Her parents, Lisa and Marc Weil, toured Europe with their comedy troupe, 'The Madhouse Company of London', with her in tow. Weil had aspirations of becoming an archaeologist in her younger years, because of the Indiana Jones film trilogy and a childhood crush on Harrison Ford. In 1984, at the age of seven, her family settled down in suburban Lansdale, Pennsylvania, a community north-northwest of Philadelphia, where her parents continue to reside. In contrast to her Gilmore Girls character, Weil was a self-avowed average student in high school who focused more on her budding acting career than her studies. Weil traveled frequently to New York City for professional auditions and acted in productions both off-Broadway and in Philadelphia's theatrical community before pursuing her film and television career. She is a 1995 graduate of the borough's North Penn High School.
Weil continues to be active in the Los Angeles theatrical community during hiatuses, is a regular performer at the Ojai Playwrights Conference in early August and radio dramas with L.A. Theatre Works, and still occasionally performs in live theater in Philadelphia and New York. She has acted with every member of her family; in 2004, she headlined with her father in a well-received community theater production of Proof at the Montgomery Theater in Souderton, Pennsylvania, just north of her adopted hometown of Lansdale. Her first ever television role in 1994, which was an episode of The Adventures of Pete & Pete called "Yellow Fever", found her playing a bully alongside her mother Lisa, who played a teacher. Her younger sister Samantha shared the screen with Liza in Gilmore Girls's third season finale, "Those Are Strings, Pinocchio". Samantha Weil played a student named Bernadette (who was unrelated to Paris) making out a video yearbook entry in front of an impatient Paris, standing off to the side waiting to make her own.
An alumna of Columbia University, Weil received her first major feature film role co-starring with Kevin Bacon in Stir of Echoes. Before that role, she was the star of the 1998 independent film Whatever, and her first film in 1996 was the short film A Cure For Serpents, where she played the daughter of a mysophobic woman bringing home a boyfriend who was not as obsessive with cleanliness, and how the mother deals with the challenge. She has also done several other short and feature-length independent films, which include Motel Jerusalem, Scar, and Lullaby, and shown interest in behind-the-camera work.
Weil was originally considered for the role of Rory Gilmore by Gilmore Girls creator Amy Sherman-Palladino before Alexis Bledel won the role; the character of Paris Geller was created especially for Weil.
Post Gilmore-Girls work
In 2006, Weil was featured in the horror themed short film Grace, in which her character suffers a miscarriage, yet decides to carry the baby to term with terrifying results. The film, which also featured Brian Austin Green, premiered at the Fangoria Weekend of Horrors convention on June 2, 2006, and is the basis for the 2009 feature film of the same name. She also had a minor role as a humane society worker in the Molly Shannon film Year of the Dog, and appeared as Doris Delay in the 2008 biographical film Neal Cassady, and as a reporter in the 2010 live-action rotoscoping film Mars, which is currently on the film festival circuit.
Weil also voiced a public service announcement which aired from June–October 2007 and aired on radio stations in Philadelphia and the Delaware Valley in support of the American Diabetes Association's Step Up to Fight Diabetes staircase climb event, which took place in Center City Philadelphia on October 20, 2007.
In 2009 Weil returned to her roots as a regular guest star in various television series, including appearances in Eleventh Hour, CSI, In Plain Sight, Grey's Anatomy and Private Practice and in February 2010 began a run as Dr. Glass on the popular Internet series Anyone But Me; series creator Susan Miller officiated at Weil's wedding to Paul Adelstein in 2006.
In March 2011 it was confirmed that Weil had signed for the role of Amanda Tanner, a White House intern, in ABC's Scandal, a series written and produced by Shonda Rhimes. It was picked up by the network for their midseason 2011-12 schedule on May 13, 2011, and Weil had a recurring role in the series' first season.
Weil played a supporting role in the horror film Smiley, and started 2013 as a recurring guest star in the last half of the only season of Amy Sherman-Palladino's ABC Family series Bunheads as Milly, the sister of Truly Stone.
At the end of February 2014, Weil was confirmed as signing on for another Shonda Rhimes series project, being cast as Bonnie Winterbottom, an assistant to Annalise Keating (Viola Davis) in How to Get Away with Murder, which premiered at the start of the 2014–15 season on September 25, 2014.
As of 2006, Weil resided in Santa Monica. She is a film and movie buff. She married actor Paul Adelstein in a wikipedia:Jewish ceremony in November 2006. They had previously known each other through theatrical projects. The two have since acted together in three film projects, the 2007 short Order Up, the 2008 Gregory Dark-helmed Frenemy, and The Missing Person. She also appeared in an episode of Private Practice on February 24, 2011, although she and Adelstein had no scenes together.
Weil became pregnant in mid-2009 with her and Adelstein's first child, a girl named Josephine Elizabeth Weil-Adelstein, born April 20, 2010. In 2006, she also became an aunt, when her sister Samantha gave birth to a child after she moved to the Los Angeles area.
Weil is left-handed, and a natural brunette. It is believed she was told to dye it dark-blonde for her Gilmore Girls role to contrast with Bledel/Rory's brown hair. After the series, she went back to her original brown hair color, though she has subsequently returned to being a blonde. Amy Sherman-Palladino has complimented Weil's skin as "the best she's ever seen in her life".