[3] Duggan signed for Newport County on 1 October 1936 and in 1939 he captained the team as they won the Third Division South title.
During the 1939–40 wartime season, Duggan also played 13 games for County in the South-West Regional League.
[6] When Duggan began his international career in 1927 there were, in effect, two Ireland teams, chosen by two rival associations.
As a result, several notable Irish players from this era, including Duggan, played for both teams.
Together with Mick O'Brien, Tommy Muldoon and Joe Kendrick, he became one of the first four English League-based players to play for the FAI XI.
On 7 November 1937 he made his final appearance for the FAI XI in a World Cup qualifier against Norway.
He made his last appearance for the IFA XI in 2–1 defeat against Scotland on 11 November 1935 After retiring as a footballer, Duggan settled in Beeston, Leeds, living in Cross Flatts Drive.