Schwab began his career as an engineer in Andrew Carnegie's steelworks, starting as a stake-driver in the engineering corps of the Edgar Thomson Steel Works and Furnaces in Braddock, Pennsylvania. He was promoted often, including to the positions of general superintendent of the Homestead Works in 1887. and general superintendent of the Edgar Thomson Steel Works in 1890. In 1897, at only 35 years of age, he became president of the Carnegie Steel Company. In 1901, he helped negotiate the secret sale of Carnegie Steel to a group of New York–based financiers led by J. P. Morgan. After the buyout, Schwab became the first president of the United States Steel Corporation, the company formed out of Carnegie's former holdings.