Apprentice to William Caslon I in London, Jackson became one of England’s most skilled and famous punchcutters, rivalling William Caslon II. However, Jackson was not apprenticed as a punchcutter; the Caslons, father and son, carried out this activity in secret. He learned his craft by watching the them at work through a spyhole, and started his own foundry in 1763. From his final premises at Salisbury Square, he became known for his ‘peculiar’ fonts, such as an Anglo-Saxon type for an edition of the Domesday Book. Vincent Figgins apprenticed for Jackson from 1782. On his death in 1792 the business was puchased by William Caslon III, grandson of Jackson’s one-time master.