Neblett studied at the University of California, Los Angeles, and in 1969, made her operatic debut with the New York City Opera, playing the part of Musetta in Puccini's La bohème. With that company, she continued to sing many leading roles, in Mefistofele (with Norman Treigle), Prince Igor (conducted by Julius Rudel), Faust, Manon, Louise (opposite John Alexander, later Harry Theyard), La traviata, Le coq d'or, Carmen (as Micaëla, with Joy Davidson, staged by Tito Capobianco), Le nozze di Figaro (as the Contessa Almaviva, with Michael Devlin and Susanne Marsee), Don Giovanni (as Donna Elvira), L'incoronazione di Poppea (with Alan Titus as Nerone), Ariadne auf Naxos (directed by Sarah Caldwell), and Die tote Stadt (in Frank Corsaro's production).
In 1976, she performed Tosca, with Luciano Pavarotti, at the Lyric Opera of Chicago. In 1977, she sang the part of Minnie in La fanciulla del West (one of her great successes), with Plácido Domingo, for Queen Elizabeth II's 25th Jubilee Celebration at Covent Garden.
In 1979, she made her Metropolitan Opera debut as Senta in Der fliegende Holländer, in Jean-Pierre Ponnelle's production, opposite José van Dam. She sang with the Met, until 1993, in Tosca, La bohème, Un ballo in maschera (with Carlo Bergonzi), Don Giovanni, Manon Lescaut, Falstaff (with Giuseppe Taddei), and La fanciulla del West.
During her career, she has sung all over the world, including in San Francisco, Chicago, Los Angeles, New York City, Buenos Aires, Salzburg, Hamburg, Los Angeles, and London. Her recordings include Musetta in La bohème, with Renata Scotto, Alfredo Kraus, Sherrill Milnes and Paul Plishka, for Angel/EMI, James Levine conducting (1979); La fanciulla del West, with Domingo and Milnes, Zubin Mehta conducting (DGG, 1977); Mahler's Symphony No.2 ("Resurrection") with Claudio Abbado, Marilyn Horne, and the Chicago Symphony Orchestra (DGG, 1977); and Marietta in Korngold's Die tote Stadt, with René Kollo, Erich Leinsdorf conducting (RCA, 1975).
She has appeared in several performances on television, including a tribute to George London at the Kennedy Center, Washington, D.C. She also appeared as a guest on The Tonight Show Starring Johnny Carson.
Miss Neblett is currently an artist in residence and voice instructor at Chapman University in Southern California. She is also on the faculty of the International Lyric Academy in Rome.
Her brief nude scene in a 1973 staging of Massenet's Thaïs, for the New Orleans Opera Association, made international headlines.Mozart: La clemenza di Tito (Troyanos, Tappy; Levine, Ponnelle, 1980)
Puccini: La fanciulla del West (Domingo, Carroli; Santi, Faggioni, 1982) [live]