[1] Duncan began acting by participating in Allan Wilkie's Shakespearian Company when it visited Launceston.
[4][6] Duncan began her career on stage by joining Melbourne's Worker's Theatre Group after university.
Her first success as a playwright was when she won the Sydney Theatre League's Playwriting competition in 1937 for The Sword Sung.
[6] Duncan worked as a scriptwriter for the film, while Ivens was the Director and Michelle was the cinematographer.
[citation needed] The Catherine Duncan Cup, awarded to the winner of an annual competition for Tasmanian amateur theatre groups, was named in her honour.