John was born in Malaysia but moved to Adelaide, South Australia, as a child to study and lived there for the rest of his life. He began work as an illustrator and designer with a large publisher, before taking up a position as a design lecturer at the School of Design, (now the University of South Australia).
In 1981, John worked with Rodney Martin to produce their first picture book There’s a Dinosaur in the Park!.
In 1985, John’s second picture book Picasso the Green Tree Frog, written by Amanda Graham, was published. John spent over three years illustrating this book and used his development of the book to demonstrate the process to his university students.
John Siow’s books have been published, translated and sold in the USA, Canada, UK, Sweden, Denmark, Austria, Germany, South Africa (English & Afrikaans), South Korea, Singapore, China (mainland and Hong Kong) and Taiwan (Mandarin).
As a lecturer in design and illustration, John influenced many students who became well-known illustrators of Australian children’s picture books.