He was involved in treaty negotiations as the United States sought to acquire more of the Menominee tribe's land in Wisconsin and Michigan for both white settlers and relocated Oneida, Stockbridge, Munsee, and Brothertown Indians.

However, Oshkosh resisted U.S. government pressure for the tribe to relocate to northern Minnesota and played a key role in securing the 235,524-acre (953.13 km2)[5] Menominee Indian Reservation as a permanent home for his people on their ancestral land.

Michigan Territorial governor Lewis Cass and Superintendent of Indian Affairs Thomas L. McKenney negotiated on behalf of the U.S. government.

[17][18][19] When the case came to trial, the jury ruled that while Oshkosh was guilty of killing Okewa, he had acted in accordance with Menominee custom and could not be convicted of murder.

Unfamiliar with the nuances of the law, the jury asked Judge James Duane Doty to render the final verdict.

They then signed a second treaty in Washington, D.C., on October 27, 1832, ceding an additional 250,000 acres (1,000 km2) to the New York Native American groups.

Native American troops were raised in Green Bay in July 1832, including Oshkosh, who was part of a band that patrolled the Mississippi River under the command of William S.

William Medill and Morgan Lewis Martin were among the representatives of the United States government, while Oshkosh was accompanied by other Menominee chiefs as well as interpreter Augustin Grignon.

Grignon's son-in-law Louis Porlier was also present and later recalled that the Menominee initially rejected the government's offer of relocating to Minnesota, at which point Morgan L. Martin approached Porlier and advised him that the Menominee "ought to make the most advantageous [treaty] they can; for if they persist in refusing to treat, the president can at his pleasure order their removal, without giving them another chance to make a treaty, and then it would be optional with him whether to them anything or nothing.

He traveled to Washington, D.C., in August 1850 to request that President Millard Fillmore allow the tribe to remain in Wisconsin.

According to Augustin Grignon, he was "only of medium size, possessing much good sense and ability, but [was] a great slave to strong drink, and two of his three sons surpass[ed] their father in this beastly vice.

"[35] However, a pioneer who knew Oshkosh recalled that while the chief was fond of alcohol, "stories to the effect that he was continually intoxicated are not true.

"[36] According to his obituary in the Shawano Venture, Oshkosh and two of his sons were under the influence of alcohol when they killed him in a fight in Keshena, Wisconsin, on August 31, 1858.

[37][38][a] His eldest son, Akwinemi, who was involved in the fight, succeeded him as head chief[39] in 1859 and held the role until 1871, when he was deposed and imprisoned for stabbing another man.