In 1965 Létourneau applied his method to about 50 violin students aged 6 to 17, at the same time undertaking to train teachers who wanted to use it. In 1969 a number of these formed the École Les Jeunes violinistes to develop new methods and study programs, and to increase and diversify the group's activities. One result was the Vivaldi Music Camp, begun in 1970 and held each summer at a different location in the Quebec City region; its purpose was to provide both teachers and students with intensive study sessions based on the Létourneau method. Beginning in 1971, voluntary groups of parents joined forces to help manage the movement's resources.
In April 1973 the Société musicale Le Mouvement Vivaldi replaced the École Les Jeunes violinistes and adopted new structures that reflected this evolution. Thus two co-ordinated organizations were founded, offering programs with regular examinations and certificates: the Académie Vivaldi with four levels for students and the Institut Vivaldi for teachers.
After having been associated with the Mouvement Vivaldi for 25 years, Létourneau left it in 1990 following an internal conflict. He then founded the Société musicale Claude Létourneau and entrusted this new organization with the sole and exclusive rights to propagate the Létourneau method. Following a signed agreement, the organizations affiliated with the Létourneau method agreed to administer the teaching of string instruments according to this one method and to respect its principles and philosophy. The workbooks and the recordings of the Létourneau method were first published by the Éditions Les Jeunes violonistes and the Éditions de la Volute, and later by the Éditions Claude Létourneau.