Oran Milo Roberts was at the center of every important event in Texas between 1857 and 1883. He served on the state supreme court on three separate occasions, twice as chief justice. As president of the 1861 Secession Convention he was instrumental in leading Texas out of the Union. He then raised and commanded an infantry regiment in the Confederate Army. After the Civil War, Roberts was a delegate to the 1866 Constitutional Convention and was elected by the state legislature to the United States Senate, though Republicans in Congress refused to seat him. He served two terms as governor from 1879 to 1883. Despite being a major figure in Texas history, there are no published biographies of Roberts. This dissertation seeks to examine Roberts's place in Texas history and analyze the factors that drove him to seek power. It will also explore the major events in which he participated and determine his historical legacy to the state.