Henry-Claudius Forestier studied at the École des Arts industriels in Geneva, where he took the woodcut class taught by Alfred Martin. His classmates were Jules Fontanez und Édouard Vallet. After a five year stay in Paris, Forestier returned to his home canton of Geneva, where he spent most of the rest of his life.

He contributed widely to illustrated magazines, and satirical reviews and is known for his striking poster designs featuring folk festivals and Swiss traditional costumes. When the Swiss national exhibition took place in Geneva in 1896, Forestier worked with Hodler to create the friezes for the Theatre Sapajou used for a Chinese shadow show. Later in life he turned increasingly to painting colorful exuberant floral bouquets as well as landscapes of the Geneva countryside.

Living modestly in Meyrin with his family, later in his life, he died in 1922 at the young age of 48, struck down by a cerebral hemorrhage while painting in plein air near his home. The Musée Rath exhibited a retrospective of his work one year after his death.