He was chosen minister at Wisbeach in 1764; at Marshfield, Gloucestershire, in 1766; at Maidstone in 1770–1, where he frequently met Dr. He is said to have founded the first unitarian church in Boston, Massachusetts.
In 1786–7 he returned, and settled at Wem in Shropshire, and while there published three volumes of sermons.
He took special interest in the materialism and necessitarianism of Hartley and Helvetius. The fragments given in the ‘Literary Remains’ show that the lectures were in part a reproduction of the ‘principles of human action.’ H. Hazlitt now finally left speculation for literature and journalism.
He became a parliamentary reporter for the ‘Morning Chronicle,’ making notes in longhand.
Hazlitt, accordingly, in the following spring went to see Coleridge at Stowey, passed three weeks there, made an excursion with Coleridge to Lynton and met Wordsworth.
A pamphlet published in 1806 was the result of Hazlitt's study of Coleridge's articles (of 1800) in the ‘Morning Post.’ Hazlitt now lived chiefly at his father's, and acquired most of the knowledge which was afterwards to be turned to account.
He had already written (in 1792) ‘A Project for a New Theory of Criminal and Civil Legislation,’ suggested by a dispute about the Test Acts; and his tutor, who had found him backward in some of his studies, encouraged him to elaborate this essay (published in his ‘Literary Remains’).
For some reason, not stated, he gave up all thoughts of the ministry about 1797.
In 1766 he married Grace Loftus, daughter of a farmer near Wisbeach.
Their first child, John, was born at Marshfield in 1767; their daughter, Peggy, at the same place; and William in Mitre Lane, Maidstone.