Young Jacques studied at the Lycée Carnot and later attended the École de droit of the Sorbonne University.
Simultaneously, he attended the Académie Julian, with several painters such as Amédée de la Patellière, Jean Crotti, Arthur Szyk.
In 1919 he joined the workshop of interior designer Marcel Mathelin, where he learned new techniques and art forms such as ink, lithography, costume projects for theater and cinema, fashion sketches and shop displays.
His friends Jean Giono, composer Arthur Honegger and his wife, concert pianist Andrée Vaurabourg, attended the exhibition which was a great success.
[c] Giono introduced him to writer and filmmaker Marcel Pagnol who shot the film Manon des Sources in Château-Chinon.
In February 1940, Paul Claudel exhibited Thévenet’s paintings at his Parisian flat,[e] which was a big success.
In 1940, Roger Allard introduced Thévenet to editors Guy Schoeller and young Robert Laffont.
[f] Around this time, several personalities and collectors purchased paintings direct from Thévenet in his Marseille studio, namely: actor and entertainer Maurice Chevalier, painter Paul Signac, Prince Pierre de Monaco, and banker, writer, and filmmaker Philippe de Rothschild.
In 1947 he traveled to Morocco and joined the "Groupe d’Émulation Artistique du Nivernais", and provided illustrations for the exhibition catalogues.
In 1953 he traveled with Giono around Italy (Rome, Orvieto, Assisi, Arezzo, Florence) and Spain (Toledo and Granada).
He helped to bring value to local painters which in the first half of the 20th century formed the School of Autun: Writer Joseph Pasquet[g] invited him to the foundation of the "Académie du Morvan" 15 July 1967.
The event took place in Château-Chinon and several personalities attended: statesman François Mitterrand, doctor and politician Léon Bondoux, law professor Jules Basdevan, historian, and archivist Régine Pernoud, writer, editor, and art critic Henri Perruchot, writer and journalist Joseph Bruley, writer and professor Jean Chatelain, businessman Louis-Philippe Bondoux, alongside the three directors: doctor and archaeologist Lucien Olivier, engineer Henri Desbruères and professor and linguist Claude Régnier.
Jean Séverin[h] wrote an article about him in the "Journal du Centre", a publication active in Nevers since 1944.