Sister to fellow authors Agnes Strickland, Jane Margaret Strickland, Susanna Moodie, and Elisabeth Strickland, Traill was the first of her siblings to commence writing. She began writing children's books in 1818 after the death of her father. Traill's first book "The tell tale": "an original collection of moral and amusing stories" appeared anonymously in 1818; she was only 16. Her early works, such as "Disobedience, or Mind What Mama Says" (1819) and "Happy Because Good", were written for children, and often dwell on the benefits of obedience to one's parents. A prolific author, until her marriage she averaged one book per year. In 1832, she married Lieutenant Thomas Traill, a retired officer of the Napoleonic Wars and a friend of her sister's husband, John Moodie, despite objections from her family (aside from Susanna). Soon after their marriage, they left for Upper Canada, settling near Peterborough, where her brother Samuel was a surveyor. Her sister, Mrs. Susanna Moodie, emigrated soon afterwards.