Born in the Alsace, Zirnheld studied at the Christian Brothers' school in Saint-Thomas-d'Aquin, Paris, then became an accountant.
In 1896, he attended a Christian workers' congress in Reims, and this inspired him to become more involved in the union, editing its journal.
[1] As leader of SECI, Zirnheld tried to maintain a course independent of both the Catholic religious hierarchy, and the secular trade union movement.
He was elected to the national industrial tribunal in 1911, and in 1913 he was the founder of the French Federation of Catholic Employees' Unions.
He chaired the conference which agreed to found the International Federation of Christian Trade Unions (IFCTU), and when it was set up, in 1920, he became vice president.