Chandler was appointed Secretary of the Interior by President Ulysses S. Grant in October 1875 and served until 1877. In compliance with President Grant's recommendations and authority, he implemented reforms in and reorganized the Department of the Interior during his tenure in office. The previous Secretary of the Interior, Columbus Delano, was not a reformer, and had carelessly allowed profiteering to spread throughout the Interior Department. Secretary Chandler fired corrupt agents at the Bureau of Indian Affairs, and fired and replaced the Indian Commissioner and Bureau Clerk. In addition, Secretary Chandler banned "Indian Attorneys" from the Interior Department, who swindled Indian tribes into paying for bogus representation in Washington D.C. Secretary Chandler fully endorsed President Grant's Peace Policy initiative to civilize American Indian tribes. To assist in fighting corruption Chandler convinced President Grant to appoint reformers Charles T. Gorman of Michigan to Assistant Secretary of Interior and Augustus S. Gaylord Assistant Attorney-Generalship of the Department of Interior. These men were instrumental helping Chandler remove internal corruption from the Department of Interior. In February 1876 Chandler handed Indians who refused to leave their hunting grounds, concerning the encroachment in the Black Hills by miners, over to Secretary of War William W. Belknap's department.
