Hillard was born at
Machias, Maine, on September 22, 1808, and he was educated at the
Boston Latin School. After graduating at
Harvard College from 1828, he taught in the
Round Hill School at
Northampton, Massachusetts and attended
Northampton Law School. He graduated at the
Harvard Law School in 1832, and in 1833 he was admitted to the
bar in Boston, where he entered into partnership with
Charles Sumner, and developed an extensive legal practice. Hillard was a
Democrat who opposed slavery and supported the
Union during the
American Civil War. He was a member of the
Massachusetts legislature: the
Massachusetts House of Representatives in 1836, and the
Massachusetts Senate in 1850. There he was conspicuous as an orator, and his policies were praised by
Daniel Webster. Hillard was a member of the Boston Common Council and served as its president in from July 1, 1846, through July 1, 1847. He was a member of the Massachusetts constitutional convention of 1853, city solicitor for Boston from 1854 until 1856, and in 1866–70 was United States
district attorney for Massachusetts. Beginning in 1837, Hillard rented rooms to
Nathaniel Hawthorne, who had recently taken a job at the customhouse in Boston. Around that time, he was a founding member of an informal social group called the Five of Clubs which also included Sumner, author Henry Russell Cleveland (1809–1843),
Cornelius Conway Felton, and
Henry Wadsworth Longfellow. Hillard was the first Dean of the
Boston University School of Law. He was also the recipient of an honorary
LL.D. from
Trinity College. Hillard devoted a large portion of his time to literature. With
George Ripley, he edited the
Christian Register, ==Public speaking==