In 1892 she expatriated herself to England (and from her first husband) as foreign correspondent for the Boston Evening Transcript, supplying that paper with approximately 120 "letters" between 1892 and 1897 before devoting herself full-time to fiction, although she remained an occasional freelance journalist for the rest of her life.

Two years after arriving in England she married magazine editor Charles Norris Williamson (1857–1920) whom she persuaded to appear as co-author for many of her books, later acknowledging her sole authorship.

Her success as an author, in its early stages, was owing to Alfred Harmsworth who, recognizing her talent, promoted her stories – especially sensational serials – in the Daily Mail and his many other publications.

Her first serial, "Confessions of a Stage-Struck Girl," appeared in Forget-Me-Not (August 11-November 17, 1894), partly inspired by her earlier career as an actress in America, as was her first novel, The Barnstormers (1897), written at the suggestion of S. R. Crockett upon hearing her describe some of her theatrical experiences at a dinner party.

Although best known for her series of motor travel romances, she was a literary polymath adept at a wide variety of genres (detective, mystery, Gothic, spy, adventure, war, ghost, fairy, satire, fictional memoir, muckraking, etc.