Denis grew up in Paris, France, alongside seven brothers and sisters. He trained as an electronic engineer and his first job was to help build a prototype of a printer that could print freshness dates on eggs. He joined an international organization, the Fourth World Movement, that sent him to the Central African Republic where he worked with local artisans to build a training center for children who worked and sometimes lived in the street. After five years in Bangui, Denis came to East New York in Brooklyn, where he ran the Street Library program. Denis learned to teach at Discovery Charter School in Newark, NJ, and after graduating from Bank Street College, joined Community Roots in Brooklyn for two years as a math teacher. He later returned to Discovery as the Instructional Leader. He keeps being amazed by all the discoveries children make every day, and how thoughtful they are. Denis lives in Jersey City with his wife, Haruko Yamauchi. He enjoys building things, eating chocolate, and hiking in the mountains.