Tozzi was born George John Tozzi in Chicago, Illinois. He studied at DePaul University with Rosa Raisa, Giacomo Rimini and John Daggett Howell. He later studied singing in New York City with Beverley Peck Johnson. He made his professional debut in the Broadway production of Britten's "The Rape of Lucretia" in 1948 as Tarquinius. His signature roles included Figaro in Mozart's "The Marriage of Figaro", Philip II in Verdi's "Don Carlos", Hans Sachs in Wagner's "Die Meistersinger von Nürnberg", and Méphistophélès in Gounod's "Faust".