Final answer:
Andrew Carnegie, a Scottish immigrant, founded the US Steel Company and implemented vertical integration to dominate the U.S. steel industry. He later became a significant philanthropist.
Step-by-step explanation:
The Scottish immigrant who founded the US Steel Company is Andrew Carnegie. Carnegie was a prominent figure in the rise of big business in the United States during the Industrial Revolution. He implemented vertical integration in his business practices, which allowed him to control every facet of steel production, from raw materials to distribution. By owning mines, foundries, and railroads, Carnegie greatly reduced costs and enhanced production efficiency, leading Carnegie Steel to dominate the U.S. steel market by 1900. After selling Carnegie Steel to J.P. Morgan, the United States Steel Corporation was formed, becoming the largest corporation in the world at that time. Carnegie's legacy extends beyond steel production; known for his philanthropy, he donated a significant portion of his wealth to educational and cultural institutions.