While in England Orczy met and married the English artist, Montague Barstow. In 1905 Orczy published her first novel, The Scarlet Pimpernel. The book was a great success but the numerous sequels such as I Will Repay (1906) and the Elusive Pimpernel (1908) sold poorly. Orczy also wrote detective fiction including The Old Man in the Corner (1909) and Lady Molly of Scotland Yard (1910).
During the First World War Orczy was actively involved in the Order of the White Feather, an organisation that encouraged women to give out white feathers to young men who had not joined the British Army.
After the Armistice Orczy moved to Monte Carlo where she continued to write novels and an autobiography, Links in the Chain of Life.
Emma Orczy died in 1947.