When he was sixteen. On leaving school in 1970 Noonan went to work for the Commonwealth Film Unit (now Film Australia), as a production assistant, assistant editor, production manager and assistant director making short films and documentaries. In 1973 Noonan was in the inaugural intake on the directors" course (along with Gillian Armstrong and Phillip Noyce) at the Australian Film Television and Radio School. In 1974 he returned to Film Australia where he worked on a number of films and documentaries, including working as assistant director on the cult movie The Cars That Ate Paris.
He co-wrote and co-directed the Australian mini-series The Cowra Breakout, wrote and directed five episodes of the mini-series, Vietnam, and made his television movie debut with The Riddle of the Stinson.
Noonan served for two years (1987-1988) as President of the Australian Screen Directors" Association, and in 1990 was appointed for a three-year term as Chairman of the Australian Film Commission. In 1995 he wrote the screenplay, with George Miller, and directed the film, Babe, his first theatrical feature.
The film earned $US280m in its 18-language world theatrical release, a further $US217m in international video sales and was nominated for seven Academy Awards (including nominations for Noonan for directing and writing). The film was recognized with many other honors, including British Academy of Film and Television Arts Award nominations for Film and Adapted Screenplay.
He co-produced the popular Davida Allen telemovie, Feeling Sexy, in 1999.
In 2006 he directed the biographical film, Mission Potter, based on the life of children"s author Beatrix Potter. Noonan has two further projects including Zebras, a drama set in the final days of apartheid South Africa and The Third Witch, a retelling of William Shakespeare"s Macbeth from the perspective of one of the witches, in development.