Marks was a member of the St. John's Wood Clique, a group of artists who meet weekly to discuss and criticize one another's works. Among them were some painters of Shakespeare whose names and pictures appear in these pages: Philip Calderon, William Yeames, and George Leslie. Marks concentrated early in his career on literary and historical subjects, but later he turned to accomplished and accurate paintings of animals. For five decades he exhibited widely at the most prestigious shows; he was elected a member of the Royal Academy in 1878.