Ambroise was born in St. Louis, Missouri, in 1801, and when he grew up, he headed southwest along the Santa Fe Trail, reaching Taos, New Mexico, in about 1822. He married a Spanish woman in 1824, became a Mexican citizen, and was working as a trapper.
In 1827, he was part of Sylvestre Pratte’s party trapping in the Colorado mountains. Years later, he was badly wounded by Southern Ute Indians, and while trying to recover with Cheyenne Indian friends, they put an end to his misery on August 15, 1842. Ambroise was also a companion of mountain man Old Bill Williams.