Born in Exeter, Devon, Hayman begun his artistic career as a scene painter in London's Drury Lane theatres (where he also appeared in minor roles) before establishing a studio in St Martin's Lane.
A versatile artist influenced by the French Rococo style, he achieved some note during the 1740s through decorative paintings executed for Vauxhall Pleasure Gardens in London, but could also turn his hand to portraits, landscapes, and scenes from history and literature.
Combining some of these, he contributing 31 pictures to a 1744 edition of Shakespeare's plays by Sir Thomas Hanmer, and later portrayed many leading contemporary actors in Shakespearean roles, including David Garrick as Richard III (1760). He also illustrated the novels of Samuel Richardson.
With Joshua Reynolds, Hayman was actively involved in the formation of the Society of Artists, a forerunner of the Royal Academy, during the early 1760s.