A speedy outside right, Dublin born Harry Duggan was picked up by First Division club Leeds United from junior Dublin football club Richmond United in May 1925, where he had scored 49 goals in the 1924-25 season. He made his Football League debut at Liverpool in October 1926 but was a fringe player playing less than 30 matches in his first five seasons at Elland Road before he established himself from the start of the 1931-32 season, his goalscoring and work rate endearing him to the fans. In 1932 he captained Leeds to promotion from the Second Division as they finished runners up.
Duggan was selected by the Irish Free State for a friendly against Italy ‘B’ which ended in a 2-1 defeat on 23rd April 1927. In October 1929 the Ireland selectors included Duggan in the team for the Home Nations Championship match with England at Windsor Park, Belfast. The game ended in a 3-0 defeat for the Irish and over the following six years he was awarded a total of eight Ireland caps. He also scored once for the Irish Free State through to his fifth and final international cap from the FAI in a 3-3 draw against Norway on 7th November 1937, a match that Eire had to win to stand a chance of qualifying for the following year’s World Cup.
Duggan left Leeds United after 49 goals in 196 appearances, signing for Newport County for £1.500 in October 1936, where he was again appointed club captain. His goals and leadership helped them to the 1939 Division Three (South) Championship. By the time the outbreak of Second World War forced the abandonment of peacetime football he had scored 20 goals in 101 appearances for County. He retired from football in March 1940 after the outbreak of the Second World War.