Her work was noted for its ability to remove clutter to tell a simple story that young children could enjoy, employing flat colours and clean lines.

She produced work for more than 50 books throughout her career, including publications by other authors, such as a 1987 edition of J. M. Barrie's Peter Pan and David Lloyd's retelling of "The Frog Prince".

Ormerod began her illustrative career in Britain after moving to England in 1980, but she returned to themes connected to her home country with Lizzie Nonsense (2004), Water Witcher (2008) and the award-winning Shake a Leg (2011) for Aboriginal writer Boori Monty Pryor.

[2] Although never planning to start a family, the birth of her first child, Sophie, Ormerod found motherhood a great boon and enjoyed the intimacy of her daughter's company.

In the 1980s she began a close working relationship with writer David Lloyd, who later became the chairman of Walker, and in 1991 they published a retelling of The Frog Prince that she illustrated.

Her drawings of his family dancing led to the two collaborating on the book Shake a Leg, which won the Australian Prime Minister's Literary Award for Children's Fiction.