He had many careers, though, including time as a Georgian politician, military officer, and bureaucrat in the United States government.

First, the President appointed Calhoun the federal Indian Agent for the newly acquired territory of New Mexico.

During his two-year tenure in that position, Calhoun used various tactics to convince or coerce Pueblo Native Americans to renounce their rights under the Treaty of Guadalupe Hidalgo as former Mexican citizens.

[1] Calhoun claimed that he only sought to "protect" the Pueblos from their Mexican-American neighbors by excluding them from territorial affairs.

He garnered the support of wealthy Mexicans who feared for their own racial status in the U.S.[2] Shortly after the end of his term as governor of the territory, Calhoun died of scurvy near Independence, Missouri, carrying his own coffin, while en route to Washington, D.C., and eventually for his home in Georgia.