He was educated at the Marree and Hoyleton primary schools before attending a Marist Brothers college in South Australia.

[1] He gained official leave from parliament[1] to join the Australian Army in 1941 during World War II, serving in the 25th Battalion seeing action in New Guinea.

Three years later, he won the seat of Toowoomba for the Labor Party in the 1935 by-election to replace the sitting member, Evan Llewelyn.

He not only had to deal with the presence of the QLP, which merged into the Democratic Labor Party in 1962, but was faced with particularly strenuous infighting within what was left of the ALP's parliamentary representation.

[1] Following the 1966 election Duggan supported Jack Houston's successful challenge to deputy leader Eric Lloyd.

Three months later on 11 October 1966 Duggan abruptly resigned as leader due to a "taxation difficulty of some magnitude" with Houston replacing him.

[1] On Boxing Day, 1935 he married Beatrice Mary Dunne at St Patrick's Cathedral in Toowoomba[4] and together had one son and one daughter.

[1] Duggan died in June 1993 and his funeral was held at St Patrick's Cathedral[5] and proceeded to the Drayton and Toowoomba Cemetery.