Ku dhammaystir weedha soo socota: Wuxuu ku dhashay Ayrshire, Duncan wuxuu dhigan jiray Ardrossan Academy ee Ardrossan, Waqooyiga Ayrshire wuxuuna wax ku bartay Jaamacadda Birmingham halkaas oo uu ka helay BCom sanadkii 1985. Kadib wuxuu u shaqeeyay sidii lataliye ganacsi iyo isgaarsiineed Mackays Stores Ltd laga soo bilaabo 1985 ilaa 1988 marka lagu daro maamulka ganacsiga dharka qoyska - John Duncan & Son laga bilaabo 1988 ilaa 2000. Bishii Sebtember 1997, wuxuu ka soo muuqday dhagaystayaasha dood ka socotay telefishanka Scottish Television oo ku saabsan
Aftidii aftida ee kala wareejinta awoodaha dowladda, wuxuuna ka hadlay ka soo horjeedka dhismaha baarlamaanka Scotland. Duncan wuxuu markii danbe isku sharaxay baarlamaankii uu markii hore ka soo horjeeday.