Bidu Sayão was born on May 11, 1902 in Rio de Janeiro, Brazil. As a small child, her father took her to concerts and operas and this early exposure instilled in her a love of music. However, as the child of a well-to-do family, her early inclinations towards a musical career were discouraged. It was her uncle who supported and arranged lessons for Sayão with the Romanian-Italian soprano, Elena Theodorini. Within a few years, she sang the Eccola! from Donizetti's Lucia di Lammermoor at the Teatro Municipal. At the urging of her teacher, she went to France to study with the Polish tenor, Jean de Reszke, who encouraged her to consider a career in opera as well as in song.

In 1926, while on holiday in Rome, she auditioned for the diva and impresaria, Emma Carelli, which resulted in a formal debut at Carelli's Teatro Costanzi as Rosina in Il Barbiere di Siviglia. By her late twenties, she had sung in many opera houses in Europe and South America including Turin, Lisbon, Milan, Naples and Rio de Janiero.

In the fall of 1935, Sayão debuted in New York at a Town Hall recital that drew the attention of conductor Arturo Toscanini who asked her to sing Debussy's cantata, La Damoiselle Elue, with the New York Philharmonic. On February 13, 1937, she was invited to sing the title role in Massenet's Manon at the Metropolitan Opera. The New York Times reported of this performance that she "..triumphed as a Manon should, by manner, youth and charm, and secondly by the way in which the voice became the vehicle of dramatic expression." From then until her retirement, she sang mostly at the Met with occasional performances at the San Francisco Opera and in South America.

During World War II, she performed in army camps and hospitals for which she was decorated by the United States Government. In Brazil, she was honored by several presidents and was awarded the most important honor of the country, the "Ordem do Rio Branco" for her contribution to music as well as for her promotion of the Brazilian image abroad.

The Brazilian soprano sang more than 200 performances of 12 different roles at the Metropolitan Opera through the 1930s and 40s and sang proficiently in Italian, French, Spanish, English and her native, Portuguese. Like many opera stars of the period, Sayão possessed jewels of impressive scale set with large stones which would have stood out both during her on stage performances and in her personal life.