Knopwood was from a respected Suffolk family and was educated at Cambridge. He obtained a Chaplaincy in the Navy and accompanied Lt. Gov. Collins to Australia in the Calcutta, acting as magistrate in the early years of the settlement. He was also the only contemporary historian at first. His diaries of life in Tasmania have provided information for later accounts of the first settlement there, and he 'appears as a benevolent figure in Price Warung's story, '"The Procession of the Buttercup"' (Oxford Companion).