John Peter Didier was reportedly a native of France. A prominent government official in the Missouri Territory, he served as Fire Captain in Saint Louis, Missouri from 1811 to 1817. In 1817, he became Territorial Treasurer, serving in that post for a year.
In 1820, he was appointed as the first State Treasurer following the signing of the state constitution, but before Missouri was officially admitted as a state.
Along with the other provisional state officeholders, he resigned when Missouri officially became a state in August, 1821. Public records indicate that he died two years later on August 25, 1823.