Identifying himself with the Democratic party, he served in the state House of Representatives in 1848, and was a prominent member of the convention for the revision of the state constitution in 1850-1851, a representative in Congress (1851-18s5), commissioner of the United States General Land Office (1855-1859), a United States senator (1863-1869), and governor of Indiana (1873-1877).
The first House of Representatives was to contain seventy-five members.
The legislature meets biennially at Augusta, the capital, and is composed of a Senate of thirty-one members and a House of Representatives of one hundred and fifty-one members.
The House of Representatives was to consist of members chosen in the different states in numbers proportioned to their population, but never fewer than five.
In 1830 he was elected a member of the House of Representatives of Louisiana, in 1831 was appointed deputy attorney-general of his state, in 1833 became presiding judge of the city court of New Orleans, and in 1834 was elected as a Jackson Democrat to the United States Senate.
Elected to the Ohio House of Representatives in 1845, he became one of the extremest of the state rights Democrats of his section, emphasizing his principles in the legislature in the local and national party conventions, and in the columns of a newspaper, the Western Empire, which he edited at Dayton, Ohio, in 1847-49.
The legislative department consists of a senate of 30 members, apportioned among the counties according to population, but with the proviso that each county must have at least one senator, and a House of Representatives of 245 members, one from each township. Since 1870 elections and legislative sessions have been biennial.
For elections to the Senate the governors of states, and for general elections of the House of Representatives the governor-general, would cause writs to be issued.
An election in August of one-half the Senate and all of the House of Representatives resulted in a Unionist majority in the new legislature of 103 to 35, and in September, after Confederate troops had begun to invade the state, Kentucky formally declared its allegiance to the Union.
His father, John Scott Harrison (1804-1878), represented his district in the national House of Representatives in 1853-1857.