With the discovery of lead ore in the region in 1826, he and his younger brother Jean Pierre Bugnion Gratiot became interested in the mineral lands of present-day Shullsburg, Wisconsin.

They eventually befriended a mixed-blood woman, Catharine Mayotte, who had doctored Susan Gratiot for a time and with whom they exchanged gifts and information.

[9] During the Black Hawk War, he exerted his influence with the Winnebago acting as an intermediary in his efforts to negotiate peace and maintain stability in the region.

[11] During this meeting, he sent Winnebago chieftain White Crow to Black Hawk's camp purchasing their freedom in exchange for horses and various trinkets valued at $2,000.

The Prophet did not remain at his lodge for long and resumed recruiting for Black Hawk in Winnebago villages upriver, however he was ultimately unsuccessful in this venture.

As American settlement of the territory continued, the native and mixed-blood population near Gratiot's Grove as well as in the areas of Galena and Dubuque had become deserted by 1833 with exception to "a few straggling Winnebagos who lingered in the country.

"[6] He resigned his position as an Indian agent the following year and, closing his mining business, he bought a section of land in which he built a small house outside of Gratiot's Grove to retire as a gentleman farmer.

"[6] Gratiot then proceeded to travel to St. Louis to acquire the necessary signatures and documentation for the Rock River Winnebagos to receive payments from General Henry Atkinson before preparing to leave for Washington, D.C. in early 1836 to clear up the matter.

[6] However, by the time he was ready to leave for the capital, few Winnebagos lived near his residence and within a year, the federal government began favoring their removal.