She learned singing at her convent school; at the age of eight, she entered the Conservatorio del Liceo in Barcelona. Her most important teachers were Eugenia Kenny, Conchita Badea, and Napoleone Annovazzi. When she graduated in 1954, she won the Liceo's Gold Medal.
Caballé made her professional debut in Madrid in the oratorio El pesebre (The Manger) by the great Catalan cellist Pau (Pablo) Casals. She then went to Italy, where she received a few minor roles at various houses.
In 1956, she joined the Basle Opera; she was working her way through the smaller roles when one of the principal singers took ill and she took over the role of Mimì in Puccini
's La Bohéme. Her unqualified success in that part led to promotion to starring roles, including Pamina (The Magic Flute), Puccini
's Tosca, Verdi
's Aïda, Marta in Eugene d'Albert
's Tiefland, and the Richard Strauss
roles of Arabella, Chrysothemis (Elektra), and Salome.
She steadily gained a European reputation, singing in Bremen, Milan, Vienna, Barcelona, and Lisbon, taking such diverse roles as Violetta (La Traviata), Tatiana (Yevgeny Onegin), Dvorák
's Armida and Rusalka, and Marie in Berg's Wozzeck. She debuted at La Scala in 1960 as a Flower Maiden in Parsifal. She sang in Mexico City in 1964 as Massenet
In April 20, 1965, on extremely short notice, she substituted for the indisposed Marilyn Horne
in a concert performance in Donizetti
's Lucrezia Borgia, achieving a thunderous success and "overnight" super-stardom. She became one of the leading figures in the revival of interest in the bel canto operas of Bellini
, many of which were staged especially for her. Caballé's performances as Elizabeth I (Roberto Devereaux) and that monarch's rival Mary Queen of Scots (Maria Stuarda) are legendary. In 1971, she sang a memorable concert performance of Maria Stuarda in which her fellow Barcelonian José Carreras
made his London debut, and after that she helped advance his career. She made her Metropolitan Opera debut in 1965 as Marguerite in Faust.
Caballé's career has centered around Verdi
's important dramatic roles, but has also embraced the Marschallin (Rosenkavalier), the Countess (Marriage of Figaro), and Queen Isabella (in the premiere of Leonardo Balada
's Cristobál Colón in Barcelona in 1989).
Caballé has had unusual crossover success. In addition to singing on two tracks on an album by New Age composer Vangelis
, she is famous for collaborating with the late Freddie Mercury
of the rock group Queen
, who wrote Exercises in Free Love for her. She appeared on his hit album Barcelona. That album and its primary single rose high on the pop charts.
In 1964, she married Spanish tenor Bernabé Marti. They have two children, Bernabé Marti, Jr. and Montserrat Marti, who is herself a succesful soprano. In 1997, Caballé co-founded an important annual vocal competition in the Principality of Andorra, the Concurs Internacional de Cant Montserrat Caballé. She conducts master classes in conjunction with that competition.