He was best known for his work as an actor in radio, but also in theatre and television in series and TV movies, both in his native England, Australia and the United States.
[1] Duncan was accepted in to the Royal Academy of Dramatic Art at the age of 16, before joining the British army, which saw him posted to various international locations,whilst with the army he served with the entertainment unit He worked for the BBC reportory company after being demobilised.
[2] He played Puck in Shakespeare's A Midsummer Night's Dream to largely but not exclusively school student audiences at the Theatre Royal in Adelaide in 1951/1952.
[1] He starred in the Australian Broadcasting Commission radio series Dr Paul as a voice actor.
[5] Later in his career, Duncan appeared in the television soap opera Home and Away.