Billed as mezzo-soprano during her career, Fedora Barbieri might more accurately have been described as a mezzo-contralto, a term reserved for dramatic voices placed slightly lower than mezzo-sopranos and with a darker coloration. While she possessed a strong top register, it could not match in ease or splendor that boasted by Giulietta Simionato, whose career roughly paralleled Barbieri's (Barbieri developed an intense dislike for her rival and unhesitatingly shared that distaste with interviewers both during and after her singing years). Barbieri recorded extensively, sometimes leaving multiple studio recordings of her most celebrated roles. Her prime years lasted into the 1960s; she thereafter began to assume smaller roles such as Mama Lucia in Cavalleria rusticana.
Barbieri did not begin formal study until her eighteenth year. While working in the shop owned by her parents, she often sang to pass the long hours. One day, a knowledgeable customer heard her and insisted that she begin voice lessons; for two years, she worked with Federico Bugamelli in her native city, followed by nine months' study with Luigi Toffolo. Her debut as a singer took place at San Giusto Church which had been the site of her baptism years before.
For advanced study, she moved to Florence where she became a pupil of the famous dramatic soprano Giulia Tess (who had herself begun her career as a mezzo soprano). Barbieri made her stage debut in Florence on November 4, 1940, in Cimarosa's Il matrimonio segreto. Her appearance as Fidalma was followed the next day by the role of Azucena in Verdi's Il trovatore. The third night, she returned to the role of Fidalma, beginning a reputation for endurance that accompanied her throughout her career.
After her beginnings in Florence, Barbieri sang for two and a half years at La Scala in Milan, initiating her relationship with that theatre as Meg Page in Falstaff. A part (Dariola) in the world premiere of Franco Alfano's Don Juan de Mañara at the 1941 Maggio Musicale Fiorentino attracted considerable attention as did her participation in two revivals of works by Monteverdi, Il ritorno d'Ulisse in patria (1942) and Orfeo (1943). In 1943, she retired for two years to begin married life as the wife of the Maggio Musicale Fiorentino director, Luigi Barlozetti. Her return to the stage in 1945 took place as Amneris in Verdi's Aida at the Teatro Verdi in Florence. Her career thereafter grew in depth and breadth as she undertook increasing numbers of roles in both the Verdi and bel canto repertories both at La Scala and elsewhere. During this decade, one of her most convincing triumphs came in the title role of Donizetti's La favorite, then a seldom-produced work.
In 1950, Barbieri was chosen by Rudolf Bing to perform the role of Princess Eboli in the new Metropolitan Opera manager's calling card production of Don Carlo. The acclaim she received in that much-heralded cast assured her presence at the Met for a total of nine seasons, during which she sang such additional roles as Amneris, Azucena, Dame Quickly, Carmen, Laura, and Adalgisa in Bellini's Norma (in which she, together with Maria Callas, opened the 1956 - 1957 season). She reprised Eboli in Covent Garden's Don Carlo of 1958.
Among her most impressive recording are her two each of Amneris and Azucena (with Milanov and Callas, respectively).