Step 1 : Introduction to the question "Who was the only U.S. president whose grandfather was also president?"
...Benjamin Harrison served as the 23rd president of the United States. He was a grandson of the 9th president, William Henry Harrison, creating the only grandfather-grandson duo to have held the office. Harrison was elected to the presidency in 1888, ousting incumbent Grover Cleveland. Hallmarks of Harrison's administration included unprecedented economic legislation, including the McKinley Tariff and the Sherman Antitrust Act. One of the lasting legacies of Harrison's presidency was the expansion of the country to include the states of Montana, Washington, Idaho, Wyoming and the Dakotas.