Sadler was born at Snelston, Derbyshire on 3 January 1780, and died at Belfast on 19 July 1835. He was the youngest son of James Sadler of Doveridge, a landowner with Methodist leanings. Sadler was educated at a school in Doveridge, and while still in his teens became a Methodist preacher, and was noted for his eloquence and persuasiveness. In 1800 he joined his elder brother, Benjamin Sadler, in business in Leeds. He married Ann Fenton, daughter of another business partner, in 1816.
From The Biographical Dictionary of British Economists in Oxford Reference.