Born into a medical family, his father Henri Forestier was a director at the therapeutic spas in Aix-les-Bains. He was awarded the Croix de Guerre and made a commander of the Légion d’honneur for his bravery in the First World War as a field doctor. Whilst completing his medical studies he excelled for the university rugby team and was called up to play for the hastily put together French team for the 1920 Antwerp Games. Forestier was also an excellent swimmer and skier.
It was in the field of medicine however that Forestier was to excel. Working with the neurologist Jean-Athanase Sicard, he pioneered radiodiagnosis in neurology with the discovery of the use of Lipidol and is also remembered for his introduction of gold salts as a remedy for rheumatoid arthritis. Forestier has the unusual distinction for an Olympian of having a disease name after him – Forestier’s disease is a degenerative spinal arthritis found predominately in elderly men.