A virtuoso bassoonist and teacher at the Paris Conservatoire, Jancourt is mostly known for his method books and the system innovations he made to the “Buffet” style bassoon.
Throughout his childhood he also learned violin and clarinet before switching to the bassoon because he was “impressed by the timbre and character” of the instrument.
He became a very prolific composer and wrote mostly bassoon “concert pieces that are very beautiful and still a joy to perform.”[citation needed] His last appearance as a performer came in 1877 in Angers, France.
Working along with his colleagues Louis Auguste Buffet, Frédéric Triébert, and Pierre Goumas, Jancourt made several key contributions to the improvement of the French bassoon that are still in use today.
They also rebuilt the bassoon with 22 keys, a more mathematically calculated ore to produce the best sound, adding 22 new trills.
Maurice Ravel, Henri Tomasi, André Jolivet, and Alexandre Tansman are prime examples.
His Grande methode is widely recognized as the most expansive and detailed bassoon tutors ever written and is still used today.