President Andrew Johnson appointed McCook to serve as the U.S. Minister to the Kingdom of Hawaii from 1866 through 1868.[1] In 1869, President Ulysses S. Grant appointed McCook Governor of the Territory of Colorado, a selection bitterly opposed by Jerome B. Chaffee, the Colorado Territorial Delegate to the United States House of Representatives. During his tenure, Governor McCook signed the legislation that created Colorado Agricultural College (now Colorado State University) and was among the first territorial governors to endorse women's suffrage. He was a member of the Republican National Committee in 1872.