Noonan arrived in Australia in 1940. After a stint in the armed forces during the second world war, he studied art at the National Gallery in Melbourne and arts/humanities at the University of Sydney (1947-50).

Noonan wrote the Twilight Ranger comic, illustrated by Keith Chatto. He also wrote the series of Flying Doctor novels, most of which were illustrated by comic artist Reg Hicks.

During his career, he was a prolific author for radio, television, film and plays, as well as children's books, short stories, novels and biography. From 1957, he lived in England, where he wrote for television and helped pioneer Australian television series such as Flying Doctor (1959). He returned to Australia in 1978/79.