Amongst the music festivals where he has appeared are the Aix-en-Provence Festival, Festival de Beaune, Festival d'Ile de France (Paris), Festival d’Art Sacré de la Ville de Paris, and the Wiener Festwochen (Vienna).
He also appeared on the international stage in productions in New York City, Vienna, Amsterdam, Tokyo, Paris as well as in concerts in Europe, Morocco, India, and Australia.
In 2003 he appeared in a series of recitals in Europe with the mezzo-sopranoMagdalena Kožená.[2] In March 2004, the French music magazine Classica featured him as a Classica RTL young talent and included the RTL Discoveries CD Thierry Gregoire chante Vivaldi et Haendel.[3] Since 2005 Gregoire has also been a voice teacher at Ecole Nationale De Musique - Charleville Mezieres.
2001 Czech Crystal Award, Golden Prague International Television Festival - Best recording of a concert or stage performance (opera, operetta, ballet, dance, musical), Magdalena Kožená and Thierry Gregoire Česká televize, Brno Television Studio, Czech Republic[4]
"Thierry Gregoire has the ideal voice for Ottone" - Sergio Segalini, musicologist and former Artistic Director of La Fenice[This quote needs a citation]