Her breakthrough came with "John Halifax, Gentleman" (1856), a novel celebrating middle-class virtues, integrity, and perseverance, which became one of the most popular books of the nineteenth century. Other notable works include "The Ogilvies" (1849), "Olive" (1850), "The Head of the Family" (1851), and "Agatha's Husband" (1853). She also gained recognition for children's literature, producing beloved fairy tales such as "The Adventures of a Brownie" (1872) and "The Little Lame Prince" (1875).
In addition to fiction, Craik wrote poetry, essays, and works on household management, including "A Woman's Thoughts About Women" (1858), reflecting her interest in women's independence and social issues. In 1864, she married George Lillie Craik, thereafter signing her works as Mrs. Craik. Her writing is remembered for its moral earnestness, warmth, and sympathy for the disadvantaged, securing her lasting place in Victorian literature.