Self-taught, he began playing the piano at age 18, later arranging for Michel Magne and Alice Dona, his first notions of orchestration taken from the books of the "Que sais-je ?"
Jean-Claude collaborated on several film soundtracks including: Les Guichets du Louvre by Michel Mitrani, La Horse by Pierre Granier Deferre, Paris Nous Appartient by Robert Benayoun, Slogan by Pierre Grimblat, Projection Privée by François Leterrier, L'amour Propre by Martin Veyron, La Nuit Tous Les Chats Sont Gris by Gérard Zingg, and Comédie d'été by Daniel Vigne.
BBC Concert Orchestra, Crouch End Festival Chorus, a children's string quintet were part of the show On 22 and 23 October 2008 this show - conceived, arranged and orchestrated by Jean-Claude Vannier - was performed at the Cité de la Musique with guest vocalists :Mathieu Amalric, B at the Cité de la Musique with guest vocalists Alain Chamfort, Mathieu Amalric, Brigitte Fontaine, Brian Molko (Placebo), Martina Topley Bird, Daniel Darc, Clotilde Hesme, Seaming To.
The rhythm section was : bass : Herbie Flowers - guitars: Claude Engel and Thomas Coeuriot - drums: Pierre Alain Dahan - keyboards : Gérard Bikialo, and a sound effects man : Michel Musseau.
In May 2019, he announced a new project with heavy metal vocalist Mike Patton, entitled Corpse Flower, with an album due in September that year.