Shortly after immigrating to the U.S. from Scotland, Carnegie became private secretary to Thomas A. Scott who was just beginning his career with the Pennsylvania Railroad. Carnegie worked for Scott during the latter's position as chief of railroad transportation for the Union during the Civil War and, at the end of the conflict, left Scott to build a successful business in the sales of railroad securities, oil brokering and bridge building. In 1873 Carnegie moved into the emerging steel industry, and he and his partners were responsible for making the U.S. steel industry the world leader by the turn of the century. After selling his enterprises to J.P. Morgan's U.S. Steel in 1901, he spent the remainder of his life traveling and supporting his various philanthropies.