After studying (clarinet) at the Conservatoire in Bern, he trained with Pierre Dervaux (conducting), and Edison Denissov (composition). He then worked with Cristóbal Halffter, Heinz Holliger, Klaus Huber and studied with Pierre Boulez at IRCAM. In addition to conducting and participating in festivals (e.g. World Music Days and L’Art pour l’Aar Festival in Switzerland), his creative work is considerable. It includes all genres from opera to choral, symphonic and chamber orchestral works.

He founded L’Ensemble ORION with his son, horn player Olivier Darbellay, and daughter, violinist Noëlle-Anne Darbellay. In 1992 in Perugia, he worked with John Cage during his last stay in Europe. That same year, he and his wife Elisabeth Darbellay premiered György Kurtág’s Lebenslauf at the WDR Festival in Witten. Jean-Luc Darbellay regularly receives commissions from major radio stations, including Radio-France, Leipzig Radio (Requiem for Soloists, Chorus and Orchestra, reprised at the Lucerne Festival in 2010) and CRPLF. Radio Suisse Romande commissioned Oyama, premiered by Orchestre de la Suisse Romande, which also played Dernière lettre à Théo in 2010. He has performed the world over, from Leipzig to Moscow, Luxembourg to Yokohama, Vienna to Hong Kong... Recordings have been made of many of his works (published by Ricordi Munich), including Jean-Luc Darbellay: a Portrait (Claves Records), rewarded by Académie Charles Cros, and Musiques Suisses - Grammont Portrait with his chamber music.

He was Composer-in-Residence 2011/12 with the Lausanne Chamber Orchestra. Cosmos for multi percussion and orchestra (commissioned by RTSR and ’OCL) premiered with Evelyn Glennie and conductor Pascal Rophé on that occasion. He was Composer-in-Residence for the “Sommets Musicaux de Gstaad” Festival in 2012.
In 2005, the French State made him Chevalier of the Ordre des Arts et des Lettres.