From humble beginnings, the company soon began to grow. In 1913, it merged with the Hamilton Malleable Iron Company to become the Dominion Steel Foundry Company. During World War I, production at its plant soared. By war’s end, 2,280 workers were on the payroll — nearly ten times the pre-war total. The company, now called Dominion Foundries and Steel, continued expanding over the next few decades, but it was not until 1951 that its first blast furnace was lit. In 1954, Dofasco became the first North American company to produce basic oxygen steel. In the decades that followed, the company employed thousands of workers to produce hot and cold rolled steel and other metal products at this plant.

Clifton Sherman, an American with years of experience in foundry management, established Dofasco in 1912. Members of the Sherman family became well-known in the local community and managed the plant for decades. The Sherman family’s control of the plant helped bolster Dofasco’s image as a “family plant.” Early on, Dofasco workers enjoyed such schemes as profit-sharing and a Christmas party that was said to be the largest such event in the world. Unlike Stelco workers, workers at Dofasco were not unionized. For a brief time, however, starting in the late 1930s, some workers in this plant were organized as Local 1004 of the United Steelworkers of America.