Flockhart was born inFreeport, Illinois, on November 11, 1964, the daughter of Kay Calista, anEnglish teacher, and Ronald Flockhart, aKraft Foods executive.[3] Her parents retired toMorristown, Tennessee, where her father lived until his death and her mother continues to reside.[4] She has one older brother, Gary. Her mother reversed her own first and middle names in naming her Calista Kay.[5]
Flockhart attendedMason Gross School of the Arts atRutgers University–New Brunswick. People began recognizing Flockhart's acting ability when William Esper (Mason Gross theater director and Flockhart's acting teacher) made an exception to policy by allowing Flockhart to perform on the main stage. Though this venue usually is reserved for juniors and seniors, Harold Scott insisted that Flockhart perform there in his production ofWilliam Inge'sPicnic. Flockhart graduated with aBachelor of Fine Arts in theater in 1988 from Rutgers as one of the few students who successfully completed the acting course. Rutgers inducted her into the Hall of Distinguished Alumni on May 3, 2003.[6][7]
In spring 1989, Flockhart made her first television appearance in a minor role in an episode ofGuiding Light as a babysitter. She also appeared in a one-hour afternoon special forLifestories: Families in Crisis, playing a teenager battling an eating disorder. Flockhart made her professional debut on the New York stage, appearing inBeside Herself alongsideMelissa Joan Hart, at theCircle Repertory Theatre. Two years later, Flockhart appeared in the television movieDarrow. Though she later appeared in filmsNaked in New York (1993) andGetting In (1994), her first substantial speaking part in a film was inQuiz Show, directed byRobert Redford.
Flockhart debuted onBroadway in 1994, as Laura inThe Glass Menagerie. Flockhart received aClarence Derwent Award for her performance.[8] In 1995, Flockhart became acquainted with actors such asDianne Wiest andFaye Dunaway when she appeared in the movieDrunks. In 1996, Flockhart appeared as the daughter ofDianne Wiest andGene Hackman's characters inThe Birdcage. Later that year, Flockhart starred inJane Doe as a drug addict, though it was not released until 1999, over three years after filming ended.[9] Throughout that year, she continued to work on Broadway, playing the role of Natasha inAnton Chekhov'sThree Sisters.
In 1997, Flockhart was asked to audition for the starring role inDavid E. Kelley'sFox television seriesAlly McBeal. Kelley, having heard of Flockhart, wanted her to audition for the contract part. Though she hesitated due to the necessary commitment to the show in a negotiable contract, she was swayed by the script and traveled toLos Angeles to audition for the part, which she won. She earned aGolden Globe Award for the role in 1998. Flockhart also appeared on the June 29, 1998, cover ofTime magazine,[10] placed as the newest iteration in the evolution offeminism, relating to the ongoing debate about the role depicted by her character.[11] Flockhart starred on the show until it was canceled in 2002.[12]
Flockhart performed in a starring role asKitty Walker, oppositeSally Field,Rachel Griffiths andMatthew Rhys, in the critically acclaimedABC prime time seriesBrothers & Sisters, which premiered in September 2006 in the time slot afterDesperate Housewives. The show was cancelled in May 2011 after running for five years. Flockhart's character was significant throughout the series' first four years, but her appearances were reduced for the 2010–2011 season, coinciding with the departure of TV husbandRob Lowe.
In 2014, Flockhart landed a role inFull Circle's second season, as mob boss Ellen. It was expected to air in 2015. This had been Flockhart's first acting role in three years, after her hiatus whenBrothers & Sisters ended.
In 2015, Flockhart was cast in the television seriesSupergirl asCat Grant, a "self-made media magnate and founder of CatCo" and boss to Kara (Supergirl's alter ego).[14] The series premiered on October 26, 2015, onCBS.[15] Due to the network's wish to reduce the show's budget, it was moved to sister networkThe CW after its first season, along with a move to filming in Vancouver. Flockhart remained with the show (albeit as a recurring character), despite her previous aversion to working outside Los Angeles.[16]
In 2024, Flockhart appeared asLee Radziwill inCapote vs. The Swans, the second season of the anthology seriesFeud.[18] Regarding playing Radziwill in an interview withThe New York Times, Flockhart said, "Truman Capote recognized that she was living in her sister's shadow... and he would say things: 'You're so much prettier. You're so much smarter. You're more interesting. You have better style.' She really needed to hear that. I think it made her really love Truman. He was fun, and she confided in him, like they all did."[19]