Margaret Hamilton was active in many aspects of children's literature, as librarian, editor, reviewer, bookseller and publisher. In 1987 she represented Australian publishers in the Children's Book Council of Australia (CBCA) cultural delegation to China. The following year she established a publishing house for children's books, Margaret Hamilton Books. A long-serving member of the CBCA, she was National President, convened the first National Conference, and established the Awards Foundation to help raise money for the Book of the Year Awards.
Hamilton was also involved in the successful campaign to preserve Nutcote, May Gibbs' cottage. Her collection of original artwork from picture books, as well as a large library, is displayed in Pinerolo, the Children's Book Cottage in Blackheath, the Blue Mountains.