Nora grew up with a passion for art. Her parents allowed her to convert the upstairs nursery of their Surrey home into her first art studio. She enrolled in Leon Underwood’s prestigious London art school, then continued her training at the Kingston School of Art and the Royal College of Art where she received a diploma in design in 1932. During these eight years of specialized training, she explored several mediums including: book illustration, pottery, wood carving, embroidery, bookbinding, mural decoration, engraving, etching, and architecture.

She is best known for her work in book illustration and wood carving. Her first commission for an illustration came at the age of eighteen. While at the Royal Academy two of her wood engravings were selected for display at the British Museum. After graduating, she began to teach part-time and illustrate children’s books. She credits a wartime job working with children and living in a rural setting as influential in her book illustrations. Her interest in children’s literature was also enhanced by her friendship with Elizabeth Yates, whom she met in London in 1937 and worked with on many book projects.

She met children’s book author Elizabeth Yates in London in 1937 and collaborated with her on many book projects; She visited Yates in New Hampshire in 1946, and remained in the United States. The natural world had provided inspiration for many of her illustrations and woodcuts and the New England flora and fauna provided many new sources for her. She subsequently moved to Wellesley, Massachusetts near Boston, where she both illustrated books at taught art, and then back to the country at Peterborough, New Hampshire.

In 1955, Unwin traveled and studied in Mexico to be closer to Boston’s cosmopolitan lifestyle. She continued to illustrate children’s books and she also began teaching art again. Soon tiring of the pace of city life, she moved back to the New Hampshire countryside in 1962. In Peterborough, she continued teaching and working closely with Yates. She remained in New Hampshire teaching, exhibiting her art, and illustrating many books until her death in 1982.

She contributed illustrations to more than 100 books by other authors, and wrote and illustrated twelve books of her own, and is also importance in the twentieth-century revival of wood engraving.She was a member of the National Academy of Design in New YorkShe earned a Newbery mention jointly with Yates for Mountain Born, and a Newbery Medal for Amos Fortune, Free Man. Among her other major works arethe detailed woodcuts for John Kieran’s 1947 Footnotes on Nature, and her children’s book The Little Mexican Duck, based on her observation of Mexican poverty during a trip there in 1955.

The Unwin family still lives in Surrey, a few in USA and Cyprus as well. A few are aspiring artists like their 'Aunt Nora'.