He moved with his family to Rhode Island when he was young and attended the common schools. After graduating from Dartmouth College in 1811, he studied law and was admitted to the bar in 1814.
He began the practice of law in Providence, Rhode Island, and practiced law there for seven years before becoming involved in manufacturing. In 1831, he was elected Governor of the State of Rhode Island, and served as governor from 1831-1833. After leaving politics, he practiced law in South Kingstown, Rhode Island until his death on June 27, 1852.
He is interred in Swan Point Cemetery in Providence.
A Whig, he served as the 12th Governor of the State of Rhode Island and a member of the United States. House of Representatives. He began his political career as a member of the Rhode Island House of Representatives, serving in the State House from 1826-1831. Arnold also served as a member of the Rhode Island Executive Council during the Dorr Rebellion from 1842 to 1843.
Following an unsuccessful attempt for a seat in the United States Senate in 1845, he was elected to the United States House of Representatives as a member of the Whig Party and served one term from 1845-1847.