Guillame de Chassy started as a classical musician, then gravitated to Indian music and jazz.

His impressive sideman resume includes work with Paolo Fresu, Gian Luigi Trovesi, Rick Margitza, Enrico Rava, David Linx, Stéphane Belmondo, Olivier Ker Ourio, Indian singer Ravi Prasad, and flamenco dancer Ana Verno. His discography as a leader includes Ithal, an Encounter with Indian Music (Mikeli Music/Night and Day, 1994), Pour Monk, A Homage to Thelonious Monk (Mikeli Music/Night and Day, 1996), Lunes: Jazz Cantata for Choir, Piano, and Percussion (Editions Hortus, 2001), for the French Minister of Culture, and Vue du Phare, La Lichere 2004).

In addition to his work as a musician, de Chassy is also an educator, and heads the Jazz Department at the Tour Regional Music School.