[1] He went to sea at the age of 16, jumping ship in South Africa and taking up an engineering apprenticeship in Simon's Town.

[2] Dunn became involved in the New Zealand labour movement, helping to establish the Greymouth Carters' and Drivers' Union and serving as vice-president of the Westland Trades and Labor Council.

The following year, Dunn moved to Queensland, Australia, where he joined the Australian Workers' Union.

He attributed the Great Depression to the "international money power, which controls the very existence of every man and woman in the capitalist-controlled countries on this earth".

[3] After his defeat, Dunn established a chemical manufacturing company whose main product was a compound analgesic marketed as a headache powder.

He remained politically involved, and at the 1938 state election stood as a candidate of the Industrial Labor Party, another breakaway group.

In 1941, Dunn's old Lang Labor colleague Eddie Ward secured him a position in the Department of Labour and National Service.

In 1932, his wife was imprisoned for one month after being convicted of forgery, uttering, and obtaining money under false pretences.

He died suddenly at his home in Dee Why on 21 November 1945, and was buried at Frenchs Forest Bushland Cemetery.