Career
He left New Orleans in 1816 after having been raised for a time by an aunt, and began working in the lower-Missouri fur trade in 1819. He later became involved in the Missouri Fur Company. Early in his career Fontenelle was involved in fur trading into the Rocky Mountains.
However starting in the late 1820s he was in command at Fontenelle"s Post in what would become Bellevue, Nebraska, along the Missouri River.
In 1831 he led a trading expedition to the Cache Valley of Utah and Idaho with Andrew Drips. On their return to Saint Louis they were joined by some Nez Perces people seeking to get Christian missionaries to come to their people.