Isobelle began the first of her highly acclaimed Obernewtyn Chronicles while she was still in high school and worked on it while completing a Bachelor of Arts and then a journalism cadetship. The first book was accepted by the first publisher she sent it to and went on to be short-listed in the Older Readers section of the Children’s Book Council Book of the Year Award. The series and her short stories have established her at the forefront of fantasy writing in Australia

She has written many award winning short stories and books for young people since then. Scatterlings won Talking Book of the year in 1992 and The Gathering was a joint winner of the Children’s Book Council Book of the Year Award in 1993 and winner of the 1994 Children’s Literature Peace Prize. Billy Thunder and the Night Gate was shortlisted for the Patricia Wrightson Prize for Children’s Literature in the 2001 NSW Premier’s Literary Awards. Greylands was named a White Raven at Bologna Book Fair and the title story of the Green Monkey Dreams collection won Best Short Story of the Aurealis Awards when it was published. Darksong won an Aurealis Award in its year, as did Alyzon Whitestarr.

Isobelle has also written many books for younger readers. She wrote The Wrong Thing which was illustrated by Declan Lee and Journey to the Centre of the Earth, illustrated by Mark McBride. The Night School illustrated by Anne Spudvilas, was shortlisted in 2011 for an Aurealis Award. The Legend of little Fur was Isobelle’s first series for younger readers. The Red Wind which she illustrated herself with pen and ink drawings won the CBCA Book of the Year in 2011 in the Younger Readers’ Category and she has just finished working on the next book in this series, The Cloud Road.

Recently Isobelle contributed to and edited a collection with Nan McNab, Tales from the Tower, Books 1 & 2. Metro Winds, a short story collection, was published in May, 2012 and The Red Queen, the final book in the Obernewtyn Chronicles was published in November, 2015.