In 1974 Isoir was appointed to the organ staff at the Conservatoire d'Orsay, in 1977 promoted to the rank of National School of Music.
In February 1974 he was awarded membership of the Friends of the Organ for his "Variations sur un psaume huguenot".
In his view, knowledge of the instrument contributes to a better approach to different musical styles in terms of both technology and performance.
Some of his most notable students have included François Espinasse, Michel Bouvard, Jean Boyer, and others.
Inheriting his father's interests, Daniel Isoir has recorded Franck's piano works.