Examples of the ideas put into practice would be the building of the National Road, the chartering of the Second Bank of the United States in 1816, and the first protective tariff, which was passed in 1816. Clay's American System was essentially in practice during the Era of Good Feelings, which corresponded with the presidency of James Monroe from 1817 to 1825.
Clay, who had served as a Congressman and a Senator from Kentucky, ran for president in 1824 and 1832 and advocated extending the American System. But by that time sectional and partisan disputes made aspects of his plans controversial.
Indeed, in the late 1820s tensions over the role the federal government should play in economic development escalated to the point that South Carolina threatened to withdraw from the Union over a tariff in what became known as the Nullification Crisis.