Born on January 1, 1747, in Morristown, Morris County, Province of New Jersey, British America,[1] Howell attended Eaton's Academy in Hopewell, Province of New Jersey,[2] then graduated from the College of New Jersey (now Princeton University) in 1766 and received an Artium Magister degree in 1769 from Rhode Island College (now Brown University).

[1] He was a Professor of Natural Philosophy at Brown University from 1766 to 1824,[2][1] also serving as a fellow from 1773 to 1824, as Secretary from 1780 to 1806, and as Acting President from 1791 to 1792.

[2] He was in private practice in Providence, Colony of Rhode Island and Providence Plantations, British America (State of Rhode Island, United States from July 4, 1776) from 1768 to 1779, and from 1781 to 1782.

[1] He was a justice of the Rhode Island Court of Common Pleas for Providence County in 1780.

[2][1] Among the prospective attorneys who studied law with Howell was Asa Aldis, who later served as chief justice of the Vermont Supreme Court.