Born in Melbourne in 1963, Garth Nix grew up in Canberra, ACT. After graduating school, Nix joined the Army reserve and enjoyed being a part-time soldier for the next five years. On a trip to England and Europe, Nix wrote a few stories, one of which, 'Sam, Cars and the Cuckoo ', became his first published short story in 1984.
Upon his return to Australia he began working at a bookstore in Canberra where he began writing his first novel, The Ragwitch (1990). He began studying at the University of Canberra and graduated with a degree in professional writing in 1996. Nix worked for several years in the publishing business in Sydney before travelling extensively. Nix undertook the overland route from London to Pakistan, tracing the footsteps of Alexander the Great. During that journey, Nix wrote part of his next book Sabriel, a fantasy novel for young adults, about a magical girl from a very different world. Sabriel received national and international acclaim winning the American Library Association Honor Book Award and the Aurealis Awards for Excellence in Australian Speculative Fiction Award for both Best Fantasy Novel and Young Adult Fiction.
Nix followed Sabriel with the standalone novel Shade's Children (1997) before returning to the Old Kingdom with a follow-up to Sabriel: Lirael : Daughter of the Clayr (2001), which won the 2002 Adelaide Festival Award for Children's Literature. The third in the series, Abhorsen, was published in 2003. Clariel followed in 2014 and the final novel, Goldenhand, in 2016. The Old Kingdom series (including collections of short stories) has won national and international awards including the Aurealis Award (four times), the American Library Association Honor Book listings (twice), and the Ditmar Award: Goldenhand was nominated for both the Carnegie Medal and a Locus Award.
His The Keys to the Kingdom is a seven book children’s fantasy series that was shortlisted for the YABBA Award for Fiction for Older Readers and the 2010 Koala Award. This was followed by The Seventh Tower and Troubletwisters Series. Nix also writes standalone Young Adult Science Fiction, Children’s Books and Children’s Fantasy such as The Ragwitch, Blood Ties, Frogkisser!, and We Do Not Welcome Our Ten-Year-Old Overlord. In 2021 he was awarded the Ditmar Award for Best Novel, the Aurealis Award for Fantasy Novel, the ABIA Award for Book of the Year for The Left-Handed Booksellers of London. The sequel, The Sinister Booksellers of Bath , again won the 2023 Ditmar Award for Best Novel. His short stories, which he began in 1984, also regularly attract award nominations: he won the Aurealis Award for Best Short Fantasy Story in 2007 with 'Sir Hereward and Mister Fitz Go to War Again'.
Throughout Nix’s life he has worked as a literary agent, marketing consultant, book editor, book publicist, book sales representative, bookseller, and as a part-time soldier in the Australian Army Reserve. He has been a full-time writer since 2001.