Carosio was taught by her father, the composer Natale Carosio in singing. At the age of 16 years, she performed in a concert hall for the first time. Then she stood as Lucia di Lammermoor on the opera stage at the Municipal Theatre of Novi Ligure.
Carosio had its greatest success in the 1930s and 1940s. She was one of the leading sopranos of Italy in the era before Maria Callas. From 1929 to 1955 Carosio was to meet regularly at La Scala. It also had engagements at the opera houses of Antwerp, Nice, Monte Carlo, Buenos Aires, the Gran Teatre del Liceu in Barcelona, the Royal Opera House Covent Garden in London and at the State Operas of Vienna and Berlin.
Towards the end of her career moved Carosio in the lyrical department and was especially successful as Violetta in Verdi's La Traviata. In addition to her opera engagements have also shot three films. After she retired, she continued to work as a music journalist and music critic in Genoa. She died on 10 January 2005.