Duncan began his career at Scottish non-league club Kirkintilloch Rob Roy, before signing for Rangers in 1957.
On 22 February 1958, Duncan made his Rangers debut in a 5–1 home win against Queen's Park.
[1] Duncan eventually fell out of favour at Rangers, competing with Scotland international Alex Scott on the wing.
Duncan made 140 Football League appearances at Chesterfield, scoring 13 times, before moving onto Chelmsford City in 1965.
[3] Duncan remained at Chelmsford for two seasons, scoring four goals in 76 appearances,[4] before moving onto Folkestone Town.