Duncan grew up in North Vancouver in Maplewood, where his grandparents had a farm (now Maplewood Farm). He moved back to North Vancouver in 2015, after living in various places, including 28 years in Toronto. He took up tennis when he returned to North Vancouver, playing at the North Vancouver Tennis Centre and public outdoor courts around North Vancouver. Duncan trained as as a lawyer, but did not work as a lawyer. He worked for, and served in many executive and board positions of, national and global labour organizations, multi-stakeholder industry organizations, pension and benefits plans, skills training and charitable organizations. Duncan has extensive leadership, governance and administrative experience, including experience in strategic planning and strategic campaigns. On the international level, he has collaborated with labour, women’s and community organizations on four continents and have overseen Decent Work projects in Mexico, Central and South America, and Africa. On the local community level, Duncan has been President of two strata councils and organized and led a neighbourhood watch group. He has served as an alumni representative on the Capilano University Board of Governors since 2017 and is currently Board Chair.