In the same year he visited Teatro dell'Opera di Roma, where he had enormous successes in the roles of Hagenbach and Rodolfo.
In 1915 he debuted at the Teatro alla Scala di Milano, in the role of Enzo Grimaldo, where he had a great success.
In 1924 he was invited to Covent Garden in London, where he first sang the role of Andrea Chénier of the opera of the same name by Umberto Giordano.
In 1929 he sang this role in the first complete recording of Andrea Chénier made together with Orchestra and Chorus of the Teatro alla Scala di Milano under the baton of maestro Lorenzo Molajoli (Naxos Historical 8.110066-67).
Marini also made his appearances outside Italy: he sang at Oper Zürich, Gran Teatre del Liceu in Barcelona and Teatro Sao Carlos in Lisbon, where he debuted in the roles of Edgardo in Donizetti's Lucia di Lammermoor, Rodolfo in Puccini's La bohème and Turiddu in Mascagni's Cavalleria rusticana.