After his failed run for the House in 1864, Long was nominated by the "states' rights" faction of the Ohio Democratic Party to make a run for governor of Ohio. Long ran against fellow Democratic candidate General George W. Morgan and "Unionist" (Republican) Jacob D. Cox. Long, with only 360 votes, was soundly defeated by Cox. Without political office, Long resumed his successful law practice in Cincinnati. Nevertheless, Long did remain active in politics and served as a delegate, or in other capacities, to the Democratic National Conventions in 1864, 1868, 1872, and 1876.