Graduated from College of New Jersey (now Princeton), 1766. Master of Arts, Rhode Island College (now Brown U.) 1769, Doctor of Laws, 1793. Master of Arts, Philadelphia College, 1769, Yale, 1772.
He was in private practice in Providence, Rhode Island from 1768 to 1779. He was a professor of law and then acting president at Brown University in 1791 and 1792. He was a Justice of the Peace in Providence in 1779, and a Justice of the Rhode Island Court of Common Pleas, also in Providence, in 1780, returning to private practice from 1781 to 1782.
He was a delegate to the Continental Congress from 1782 to 1785, and an Associate Justice of the Rhode Island Supreme Court from 1786 to 1787, then serving as Rhode Island Attorney General in 1789.
He was a Boundary commissioner, New York City in 1794. He was appointed by Thomas Jefferson in 1801 as United States Attorney, and On November 13, 1812, Howell was nominated by President James Madison to a seat on the United States District Court for the District of Rhode Island vacated by David L. Barnes.
Howell was confirmed by the United States Senate on November 16, 1812, and received his commission the following day. He served on the federalist (pro-Constitution) committee which negotiated an end to William West"s armed anti-federalist protest on July 4.
1788. Howell served until his death, in 1824, in Providence.
Member board fellows, 1773-1824, secretary
Married Mary Brown, September 30, 1770, 5 children, including Jeremiah.