Duncan was born in the Windrock coal-mining camp overlooking the town of Oliver Springs, Tennessee, United States.
[3] He served in the US Air Force, and in 1952 was garrisoned in Cambridgeshire, England, where he met and married a local girl, Betty, in 1953.
[3] When performing for American servicemen at Bushey, Hertfordshire, in 1956, he was seen by Dickie Bishop, banjoist in Chris Barber's Dixieland jazz band.
[2][4] Guided by record producer Denis Preston, Duncan then formed a new band, the Blue Grass Boys, with Donegan's former guitarist Denny Wright together with drummer Lennie Hastings and bassist Jack Fallon.
Duncan briefly became a star in Britain, touring with Wee Willie Harris, Cliff Richard, and American singer Marvin Rainwater, and appearing regularly on BBC radio and the TV show Six-Five Special,[3] produced by Jack Good.