His half-brother, Jean Pierre Chouteau, 1758–1849, b. New Orleans, also devoted himself to the fur trade. He worked for René Auguste for many years and extended the trade into present-day Oklahoma, where he established (1796) the first permanent white settlement at Salina. After becoming (1804) U.S. agent for the Osage, he struck out on his own and with others founded (1809) the St. Louis Missouri Fur Company. One of the wealthiest men in St. Louis, he spent the last years of his life on a large plantation outside the city. Two of his sons, Auguste Pierre and Pierre, continued in the fur trade.

Auguste Pierre Chouteau, 1786–1838, b. St. Louis, who graduated from West Point in 1806, resigned (1807) from the army and became (1809) a member of the St. Louis Missouri Fur Company, taking part in several expeditions. He served as a captain of the territorial militia in the War of 1812. While on a trading expedition to the upper Arkansas River in 1817, he was captured by the Spanish and imprisoned at Santa Fe for several months. After his release he continued to trade with the Osage and made his home at Salina, Okla. In 1832 he led a party including Washington Irving from St. Louis to his post; the journey is described by Irving in Tour of the Prairies (1835).

Pierre Chouteau, 1789–1865, b. St. Louis, early entered his father's business and accompanied him on several expeditions until 1813, when he and a partner formed their own merchandising and Native American trading firm. In 1831 he became a member of Bernard Pratte and Company, which was the Western agent of the American Fur Company. With the withdrawal of John Jacob Astor from the American Fur Company in 1834, Pratte, Chouteau and Company bought all the Missouri River interests of the old company. Reorganized (1838) as Pierre Chouteau, Jr., and Company, its business extended from the Mississippi to the Rockies and from Texas to Minnesota until its dissolution in 1864. One of the most powerful men in the West, Chouteau also invested heavily in railroads, rolling mills, and mining. He became one of the leading financiers of his time and lived his later years in New York City.