George Enescu recommended him and his brother Valentin Gheorghiu - pianist, for a scholarship at the Conservatoire de Paris, where he studied the violin with Maurice Hewitt and musical harmony and counterpoint with Noel Gallon.
The jury consisted of Yehudi Menuhin, David Oistrakh, Henryk Szeryng, André Gertler, Nadia Boulanger and George Georgescu.
During his 40 years of concert activity, Stefan Gheorghiu played more than 2000 performances in his native country and touring in Europe, USA, Canada and Asia.
Among the most important musical centers that had him as a guest were Paris, Menton, London, Manchester, Rome, Vienna, Salzburg, Locarno, Lausanne, Basel, Prague, Warsaw, Berlin, Munich, Leipzig, Moscow, Sankt Petersburg, Riga, Talin, Sofia, Athens, Thessaloniki, Montreal, San Francisco, Los Angeles, St. Louis, Boston, Peking, Shanghai.
He worked together with conductors Frans Konwitschny, Constantin Silvestri, Kyrill Kondrashin, George Georgescu, Jean Périsson.