[1] She made her stage debut in Hamburg, as Aida and Santuzza, later appearing in Berlin, Vienna, London.

In 1938, she created, in Hamburg, the role of Hester Prynne in The Scarlet Letter, an opera composed by her brother Vittorio Giannini (1903-1966).

After the war, she continued appearing in Paris, London, Berlin, and Vienna, and then turned to teaching, notably in Zurich.

Giannini's voice was a true dramatic soprano, backed by strong temperament and fine musicianship.

Giannini's sister, Eufemia Giannini-Gregory, was a respected voice teacher at the Curtis Institute of Music in Philadelphia and taught Frank Guarrera, Judith Blegen and Anna Moffo.