In 1769 Garnier joined the orchestra of the Royal Academy of Music (which was to become the National Opera of Paris after the Revolution), playing oboe and flute.
"[3] As oboist and flautist with the Paris Opera, Garnier participated in the premiere performances of many of the works of Grétry, Méhul, Gluck, Cherubini and Gossec, each under the composer's own direction.
He also participated in the French-language premieres of many of Mozart's works, including Les Noces de Figaro, Don Juan and La Flûte enchantée.
[citation needed] Music critic Jacques Rouchouse wrote a biography of Garnier in 2003.
Oboist Claude Villevieille is largely responsible for the reintroduction of Garnier's concert works into the public awareness.