Newton was born in London. With poet William Cowper, he was the author of many hymns. He was the son of a shipmaster in the Mediterranean service, with whom he sailed until 1742. In 1743 he was pressed into naval service, became a midshipman, deserted, was recaptured and reduced to the ranks, exchanged to a ship in the African station, became servant to a slave-trader, and was rescued in 1748, being converted on the way home in a storm at sea. The date was May 10, 1748, an anniversary he observed for the rest of his life.
He continued at sea till 1754, meanwhile studying Latin and the Bible. He was surveyor of tides at Liverpool, England from 1755 to 1760, where he heard George Whitefield and John Wesley, and studied Greek, Hebrew, and Syriac.
In 1763 he was brought to the notice of Lord Dartmouth by Thomas Haweis, through whose influence he was made deacon and priest in 1764, and given the curacy of Olney. In 1767 Cowper settled there, and the result of their friendship was the Olney Hymns (London, 1779 and often), which greatly influenced English hymnology. Other well-known hymns by Newton include "Approach, My Soul, the Mercy Seat", "Come, My Soul, Thy Suit Prepare", and "Glorious Things of Thee are Spoken".
In 1780 Newton accepted the offer of the benefice of St. Mary Woolnoth with St. Mary Woolchurch, London, where he officiated till his death. He was a strong supporter of Evangelism in the Church of England, and was a friend of the dissenting clergy as well as of the ministry of his own church. John Newton died in London and is buried in Olney.
Hardly less famous than the Hymns was his Authentic Narrative of Some . . . Particulars in the Life of John Newton (London, 1764, 9th. ed., 1799; an account of his early life). He wrote also, Sermons Preached in . . . Olney (1767); Omicron: Twenty-six Letters on Religious Subjects (1774; subsequent editions, in which the number of the letters became forty-one); Cardiphonia; or, the Utterance of the Heart in the Course of a real Correspondence (2 vols., 1781); Letters to a Wife (2 vols., 1793), and other works.
A collected edition of his works was issued by his executors (6 vols., London, 1808; new ed., 12 vols., 1821).