Highly interested in finance after this experience, Calhoun left his law practice in 1896 and became a business financier. His primary backers were the investment banks of Alex. Brown & Sons, Brown Bros. & Co., and the Maryland Trust Company. He invested heavily in street railways, directing or reorganizing systems in Baltimore, Maryland; Philadelphia, Pennsylvania; and St. Louis, Missouri. Calhoun moved to Cleveland, Ohio, in 1896. Calhoun had purchased of wooded land atop the heights east of the city in 1890. He now began development of that land into a new planned community for the wealthy and upper classes, and named it Euclid Heights.