Born in Padua, Boito studied music at the Milan Conservatoire. The premiere of his only finished opera, Mefistofele, based on Goethe's Faust, came in 1868. The premiere was badly received, but Boito's revised version was a great success, and it is still frequently performed and recorded today. Other than this work, Boito wrote very little music, completing but later destroying another opera, Ero e Leandro, and leaving a further opera, Nerone, incomplete at his death. Mefistofele is the only work of his performed with any regularity today.
As well as writing the libretti for his own operas, Boito wrote them for other composers, the most notable examples being for Giuseppe Verdi's Falstaff and Otello, and Amilcare Ponchielli's La Gioconda.
Boito was director of the Parma Conservatoire from 1889 to 1897. He died in Milan.