When he was in office, Harley promoted the careers of Jonathan Swift, Alexander Pope, and John Gay. He also wrote "with them" as a member of the Scriblerus Club. He, along with The 1st Viscount Bolingbroke, contributed to the literary productions of the Club. His particular talent lay in poetry, and some of his work (always unsigned) has been preserved and may be found among editions of Swift's poetry. Additionally, he likely had some hand in the writing of "The Memoirs of Martinus Scriblerus," though it is impossible to tell how much.