Was a member of one of Guernsey's oldestablished families and had a successful career as greffier (Clerk of the Royal Court), a position he inherited from his father in 1768. He was something of a polymath with wide interests across the natural sciences and humanities. He compiled the first known list of Guernsey plants (supported by a herbarium which still survives) and was instrumental in bringing Guernsey's antiquarian riches to the attention of the outside world. He is known to have inspired his young cousin Frederick Corbin Lukis in the pursuits of archaeology and natural history.Joshua Gosselin was also an artist and recorded the topography of his native island in a charming eighteenth century manner.