Léon Germain Pelouse was a self-taught French painter born in Pierrelaye (Val-d'oise, France). At sixteen, he began working as a traveling salesman. He began painting when he was twenty, as he was serving in the French army as a conscript. His professional painting career began at twenty-seven, with the exhibition of his Les Environs de Précy (Near Précy) at the Salon de Paris of 1865. Despite severe criticism, he continued painting.

He moved to Brittany, and there, inspired by nature around Pont-Aven and Rochefort-en-Terre, Pelouse painted landscapes which were exhibited at the Salon de Paris in the following years. He received his first medal in 1873 for Vallée de Cernay (Cernay Valley). He finally gained success and critical approval. The French government bought many of his works which are now in the holdings of museums including the Musée d'Orsay, the Musée Malraux, and the Musée des Beaux-Arts de Nantes.

By his adoption of his wife's son, Lucien Jean Léon Raingo-Pelouse, he was the grandfather of the French artist Germain Raingo-Pelouse [fr] (1893-1963; their lifespans did not overlap).

Pelouse and his friends and students who socialized and painted together in the region have become known as the École de Cernay