[1] In December 1746 Watson took holy orders and entered on the curacy of Runcorn, Cheshire; but moved three months later to Ardwick, Manchester, where he was also tutor to the sons of Samuel Birch.

His major works were: The History and Antiquities of the Parish of Halifax, 1775, 4to, a second edition of which was begun in 1869 by F. A. Leyland, but left unfinished; and Memoirs of the Ancient Earls of Warren and Surrey and their Descendants, Warrington, 1782, 2 vols..

The latter was heavily illustrated attempt to prove that Watson's patron, Sir George Warren, was entitled to the earldom of Warenne and Surrey.

He made extensive manuscript collections relating to local history, particularly of Cheshire, which were preserved, and were used by George Ormerod, John Parsons Earwaker, and other antiquaries.

Gilbert Wakefield, who was Watson's curate at Stockport and married his niece, describes him as one of the hardest students he ever knew, as well as an agreeable man.