Benjamin Harrison practiced law in Indianapolis before entering national politics through the Republican Party. During the Civil War he raised an Indiana regiment and commanded troops in the Union army, including service in the Atlanta campaign. He returned to law and party work, serving in the United States Senate from 1881 to 1887. In 1888 he defeated President Grover Cleveland in the Electoral College despite receiving fewer popular votes.

As president from 1889 to 1893, Harrison supported protective tariffs, veterans' pensions, and a stronger federal economic role. He signed the McKinley Tariff, the Sherman Antitrust Act, and the Sherman Silver Purchase Act in 1890. These measures reflected industrial and western interests. The antitrust law established a lasting federal instrument against restraints on commerce, though early enforcement was weak. The silver law contributed to controversy over the currency and strained gold reserves.

Harrison urged federal protection of Black voting rights, but the proposed elections legislation failed in the Senate. His administration also expanded forest conservation through the reserve authority provided in 1891. Six states entered the Union during his presidency. Western expansion accompanied coercive policies toward Native peoples, and the army's killing of Lakota people at Wounded Knee in 1890 occurred under his administration.

In foreign affairs he worked with Secretary of State James G. Blaine on Pan-American cooperation and reciprocal trade, supported naval growth, and confronted disputes involving Chile, Samoa, and the Bering Sea. Near the end of his term he submitted a treaty to annex Hawaii after the overthrow of Queen Liliuokalani, but annexation was not completed. Cleveland defeated him in the 1892 election. Harrison returned to legal practice and later represented Venezuela in its boundary arbitration with Britain. He was President William Henry Harrison's grandson, distinct from the Virginia Declaration signer.