Politically, Dorrington was active in Republican politics. He was elected to the House of Representatives (lower house) during the 1877 and 1883 sessions of the territorial legislature. He was a member of the Council (upper house) during the 1881, 1885, and 1889 sessions. Dorrington represented Arizona Territory as a delegate to the 1896, 1900, 1904, and 1908 Republican National Conventions. In July 1897, Governor Myron H. McCord appointed him Superintendent of prisons. Socially, Dorrington was a 33rd degree Mason.