As a playwright Duncan has worked with Imaginate, Tramway, Active Inquiry, Out of the Blue, Village Pub Theatre, Charioteer Theatre and Piccolo Theatre, Milan.  He has presented a music show at the Edinburgh Festival Fringe and was the winner of the Rowan Tree Playwriting Competition 2013.

He has extensive experience working with young people aged 8-18 as well as 18-25 and up using a devising process. He has written and developed many scripts for and with children and young people for Strange Town and has worked in many primary schools throughout Scotland.