The new company survived the founder's crisis and in 1899 acquired the Westfalia coal mine with its associated Kaiserstuhl coke plant.

During the Weimar Republic, Hoesch was one of the few heavy industry companies not integrated into the United Steel Works.

During the air raids on the Ruhr region, the facilities were nearly completely destroyed — the remaining portion was intended to continue production after World War II under the name Dortmunder Paraffinwerke GmbH but fell victim to the demilitarization orders of the Western Allies.

Amidst the peak of the steel crisis, Hoesch merged in 1972, on the initiative of Fritz Harders, with the Dutch Koninklijke Hoogovens to form the Estel Group.

However, the collaboration was terminated in 1982 at the behest of then Hoesch CEO Detlev Rohwedder, who was convinced that the corporate cultures were incompatible and that the Dutch steel managers were disadvantaging the interests of the Dortmund business units.

This hostile takeover thus became the first leveraged buyout of a German stock corporation in the history of the Federal Republic of Germany.

Friedrich Springorum represented Hoesch AG at the Secret Meeting of 20 February 1933, at which prominent industrialists met with Adolf Hitler to finance the Nazi Party.