Henri Stewart was born in the Choctaw Nation to a Choctaw father and a white mother. Though accounts of his education and employment vary, he was well educated and trained as a physician.
Why he did not continue to work in that field is not clear. In 1874, he was tried and acquitted on grand larceny charges.
In 1878, he and his cousin, Wiley Stewart, were arrested for selling alcohol in Indian Territory. When an associate, Dr. Jones, refused to bail them out, they threatened him and, ultimately, shot and killed him in Caddo, Indian Territory.
The Stewarts then fled. Henri Stewart was arrested in Missouri on August 30, 1878. Transported to Fort Smith, he was convicted and sentenced to death in June 1879.
Henri Stewart was hanged at Fort Smith on September 5, 1879.