It initially focused on lobbying for legislation to improve working conditions, and encouraging affiliated unions to merge.
[1] In its early years, the SK made some headway in obtaining compensation for workplace injuries, and a state pension.
In 1913, the union led another general strike, and this proved more successful, ultimately leading to universal suffrage in 1919.
Around this time, it also secured the right for state employees to join unions, and the abolition of a law which targeted radical trade unionists with lengthy prison sentences.
The 1930s saw the economic situation worsen, and some gains were lost, but a major strike in 1936, led by the SK but backed by the General Confederation of Liberal Trade Unions of Belgium and the Confederation of Christian Trade Unions, obtained major gains including paid leave, a minimum wage, and a 40-hour working week for many workers.