Born in Loftus-by-Cleveland, Dack received a basic education at Skinningrove Council School but, while still a child, began working in the local ironstone mines.
He represented the union on various bodies, including serving on the executive of the Miners' Federation of Great Britain, attending the Trades Union Congress and Labour Party conferences, and three international conferences of miners: in Brussels in 1910, Carlsbad in 1913, and Prague in 1925.
[1] At the 1918 United Kingdom general election, Dack stood as the Labour Party candidate for Cleveland, taking a close second place, with 35.3% of the vote.
He continued political activity at a more local level, serving on both North Riding County Council and the Guisborough Board of Guardians from 1924.
[2] The miners' association became part of the National Union of General and Municipal Workers in 1932, but retained significant autonomy even after the merger, with Dack continuing as a full-time agent until his retirement in 1936.