Nikolaus Gross was born in Niederwenigern (Hattingen/Ruhr, and, like his father, a miner. He furthered his knowledge in evening courses at the People's Association for Catholic Germany (Volksverein für das katholische Deutschland). In 1920, he gave up his job as a miner and became a youth secretary at the Christian Mineworkers' Trade Association (Gewerkverein Christlicher Bergarbeiter) in Oberhausen. From July 1921 until May 1922, he was assistant editor at the association newspaper, the Bergknappen in Essen. From June 1922 until October 1922, he was a trade union secretary in Waldenburg in Lower Silesia, and afterwards for two years in Zwickau, Saxony, and for another two years (December 1924 to December 1926) in Bottrop. In January 1927, he changed jobs to become an editor at the Westdeu