Agnes ('Nessie') Mary Gwynne was the third of four children born into a prosperous pioneering family at Werai on the Edward River, downstream from Deniliquin. She spent most of her childhood at Herne Hill, just outside Geelong, and her adult years in Lorne and Toorak. In her later years, Gwynne made several trips to England, and she also undertook sea journeys to Java and Papua.
Between 1908 and 1935, Agnes Gwynne published two plays and five novels, the last of which, the historical romance High Dawn, was published posthumously. Her protagonists are generally wealthy, independently minded, young women. Recurring themes in Gwynne's books include inheritances, political debates over the merits of socialism vs capitalism, and sheep farming. Romantic love is a regular feature in the novels and several are set in Victoria's Western District.