[1] He began his involvement in politics with an election to local council then moved to the New South Wales Legislative Assembly from 24 June 1895 to his death on 11 April 1912, serving as Treasurer in his final two years.

[2] Throughout his parliamentary career, Dacey campaigned for a garden suburb which would provide government-owned, low-cost housing to the working class.

[1][5] By 1901 he was helping to organise the Wool and Basil Workers' Federation of Australia in Sydney[6] and served as the Union's Secretary until his death.

[1] A Roman Catholic, Dacey was influenced in his political opinions by protectionism and the rerum novarum,[1] which supported people's right to join trade unions.

[1] He was an anti-billite, meaning that he was against Federation,[8] and spoke against it, for example at Coraki, New South Wales on 15 June 1899, based on his opposition to free trade.

[2][10] Dacey became a senior party figure in the late 1890s and began to work on political strategy to win support in suburban seats and from white-collar voters.

[1][2] Dacey died of chronic nephritis[11] while serving as the Colonial Treasurer and was granted a state funeral, which took place in St Brigid's Church in Marrickville, New South Wales and was well attended; a contemporary newspaper reported that along "the entire route of the procession, the footpaths were thick with people.