In the mid-1950s, she was signed to a contract by MGM, which cast her in various roles in such films as Moonfleet with Stewart Granger and Meet Me in Las Vegas with Cyd Charisse and John Brascia.

[3] She then played in the Jerry Lewis vehicle The Sad Sack, King Creole with Elvis Presley, and The Young Lions with Montgomery Clift, Dean Martin and Marlon Brando.

In 1982, she drew the attention of critics and audiences for her performance in Nine, with Raúl Juliá, for which she won both the Tony and Drama Desk Award for Best Featured Actress in a Musical.

She is featured in the recording of the 1985 concert version of Follies staged at Avery Fisher Hall, and she has starred in musicals such as Irma La Douce, Gigi and Hello Dolly!.

She took part in the recording of the album The Divas with Joan Baez, Thelma Houston, Sally Kellerman, Christine Deaver, Debbie de Coudreaux, Francine Reed, Juliana Rambaldi and Kristin Clayton in 2006.

She returned to Teatro ZinZanni in June 2009 to reprise the role and in September 2011 in the show Bonsoir Liliane!, starring with Kevin Kent, directed by Tommy Tune and choreographed by Tobias Larsson.

In December 2010, Kaye Ballard, Montevecchi and Donna McKechnie starred in From Broadway with Love, directed by Richard Jay-Alexander and staged at the Lensic Theater.

[8] In March 2015, Montevecchi won critical praise for recreating her Tony-nominated role of Grushinskaya in Grand Hotel: The 25th Anniversary Reunion Concert at 54 Below in New York City.