A native of Saratoga County, New York, Henry Millard moved to Missouri with his family while still a child. As a young man he moved to Natchez, Mississippi, where in 1826 he married Mary Warren Beaumont. While living in Natchez they became the parents of two sons, and Millard opened a mercantile business with his brother-in-law, Franklin Beaumont. the family relocated to New Orleans in 1832, and Millard went into partnership in a drugstore with Samuel Mason.
After his partner's death in 1833 and his wife's death in 1834, Millard migrated to Texas in 1835. with his new partner, J. P. Pulsifer, he bought land along the Neches River between the settlements of Santa Anna and Tevis Bluff. He laid out a townsite and named it Beaumont, his wife's maiden name.
Embracing the political life of his new homeland, Millard served as a delegate to the Consultation of 1835 and, as a Lt. Colonel in the Texas Army, commanded infantry at the Battle of San Jacinto. He later served as chief justice, alderman, and justice of the peace in Beaumont and Jefferson County, as well as tax assessor in Galveston after his move there in 1842. He died in Galveston in August 1844 and was buried there in the Episcopal Cemetery.