In 1871 he founded the Eisen-und Stahlwerk Hoesch AG, later the Westfalenhütte in Dortmund, Westphalia.
[1][2][3] In 1846, Hoesch's father expanded the family business, founding a rolling mill in Eschweiler and acquiring ten additional mine fields.
After the death of his uncle Eberhard on 21 April 1852, Leopold became the new head of the company.
During the 1860s, Hoesch moved the company's headquarters to the Ruhr area in order to benefit from low freight costs and the proximity to the coal mines.
Together with his sons Wilhelm (1845-1923) and Albert (1847-1898), as well as with the sons of his uncle Eberhard, Viktor and Eberhard Hoesch, on 1 September 1871 he founded the "Eisen- und Stahlwerk Hoesch" in Dortmund.