Benanti made her Broadway debut as an ensemble member and later as Maria von Trapp in the 1998 revival of The Sound of Music.

Benanti was born in New York City to Linda Wonneberger, a vocal coach and former actress, and Martin Vidnovic, a Broadway actor and singer.

and won a Paper Mill Playhouse Rising Star Award for Outstanding Actress in a high school production.

[7] In 1998, Paper Mill's then-artistic director Robert Johanson recommended Benanti for the role of Liesl in a Broadway revival of The Sound of Music.

"[4] When she was cast in The Sound of Music, Benanti had attended New York University for two weeks; the dean recommended she go on leave to take the job.

[8] In 1999, Benanti appeared in the Broadway revue Swing!, for which she received a Tony nomination for Best Performance by a Featured Actress in a Musical.

She also appears as a guest artist on the Gay Men's Chorus of Washington, D.C.'s live album, You've Got to Be Carefully Taught: The Songs of Hammerstein & Sondheim, taken from a 2002 performance at the Kennedy Center.

Eight months after her initial injury, Benanti was rediagnosed and received surgery that could have damaged her voice but was successful, though as of 2005 she still experienced neck pain and myelopathy.

staged concert production at the New York City Center as Louise, alongside Patti LuPone as Rose and Boyd Gaines as Herbie.

Benanti appeared in The Public Theater's world-premiere production of Christopher Durang's play Why Torture Is Wrong, And the People Who Love Them from April 6 to 26, 2009.

[22] She next appeared in the Lincoln Center Theater's production of Sarah Ruhl's In the Next Room (or The Vibrator Play) beginning previews on October 22, 2009, and opening on November 19, 2009, at the Lyceum Theatre.

She received a Tony nomination and won the Drama Desk and Outer Critics Circle Awards for Best Featured Actress in a Musical for her performance.

[26] In 2011 and 2012, Benanti had a recurring role on Law & Order: Special Victims Unit as Detective Nick Amaro's wife.

[29] In June 2013, Benanti performed as the soprano soloist in the San Francisco premiere of Andrew Lippa's oratorio, I Am Harvey Milk.

[38] In 2014, she was cast as country singer Sadie Stone in the ABC musical drama series Nashville for its third season, recording and performing several songs during her arc.

staged concert production of Frank Loesser's The Most Happy Fella alongside Shuler Hensley, Cheyenne Jackson, Jay Armstrong Johnson, and Heidi Blickenstaff.

[42] In July 2017, it was announced that Benanti would not return to the series for its third season due to her work schedule and that Erica Durance would assume the role of Alura.

[46] Benanti starred in the lead role of Amalia Balash in the 2016 Roundabout Theatre Company Broadway revival of She Loves Me opposite Zachary Levi.

[51] In 2017, Benanti once again acted on Broadway in Steve Martin's comedic play Meteor Shower, along with Keegan-Michael Key as Gerald, Amy Schumer as Corky, and Jeremy Shamos as Norm.

[52] Benanti replaced Lauren Ambrose as Eliza Doolittle in the Broadway Lincoln Center Theater revival of My Fair Lady, beginning October 23, 2018, for a limited run through February 17, 2019, except for Tuesday nights with Kerstin Anderson in the role.