Harrison was elected as President of the United States in 1888, defeating the Democratic incumbent Grover Cleveland. As President, Harrison's administration saw the passage of significant economic legislation, including the McKinley Tariff, which imposed historic protective trade rates, and the Sherman Antitrust Act. Harrison facilitated the creation of the National Forests through an amendment to the Land Revision Act of 1891. He also substantially strengthened and modernized the Navy. He proposed federal education funding as well as voting rights enforcement for African Americans during his administration, but was ahead of his time in both of those initiatives.
His administrations saw large surplus revenues from the tariffs, which resulted in federal spending reaching one billion dollars for the first time during his term. But Harrison was defeated by Cleveland in his bid for re-election in 1892, due to the growing unpopularity of the high tariff and high federal spending. A month before the election, his wife Caroline died. Harrison ceased his campaign, and out of respect so did his opponent Grover Cleveland.
After his defeat, Harrison returned to private life in Indianapolis and resumed his law practice. In 1896, Harrison at age 62 remarried, to Mary Scott Lord Dimmick, the widowed 37 year old niece and former secretary of his deceased wife Caroline. Harrison's two adult children disapproved of the marriage and did not attend the wedding. Benjamin and Mary had one child together, a daughter named Elizabeth.
In 1900, Harrison served as an attorney for the Republic of Venezuela in their British Guiana boundary dispute with the United Kingdom. An international trial was agreed upon and he traveled to Paris where he spent more than 25 hours in court. Although he lost the case, his legal arguments enhanced his international reputation as an advocate.
Harrison developed influenza or grippe in February 1901. He was treated with steam vapor inhalation and oxygen, but his condition worsened. He died from pneumonia at his home on Wednesday, March 13, 1901, at the age of 67. Harrison is buried in Indianapolis's Crown Hill Cemetery, next to Caroline. After her death, Mary Dimmick Harrison was buried next to him.
In the American Presidents Series biography of Harrison entitled Benjamin Harrison by Charles W. Calhoun, the author concludes the book on Harrison at pages 165-6 as follows:
In early March 1901, Harrison again fell ill with an acute case of the grippe, which soon progressed into pneumonia. With his wife of five years the only family at his bedside, he died on March 13, 1901. The next day President McKinley issued a proclamation of mourning, noting that "in the high office of President," Harrison had "displayed extraordinary gifts as an administrator and statesman."
To himself, McKinley perhaps also acknowledged that he owed something of his own success in the White House to the example Harrison had set. Benjamin Harrison had not set out to transform the presidency, but he was hardly a mere caretaker between the two terms of Grover Cleveland. In his own right, Harrison made important contributions to the evolution of the office. He entered the presidency strongly committed to a set of principles and policies. In defense of those ideas and in pursuit of what he thought to be his duty, he expanded the boundaries of presidential activism. Both publicly and behind the scenes, he effectively intervened in the deliberations of Congress and posted a remarkable record of legislative achievement. He resisted the dictation of party bosses in the matter of appointments, thereby risking his own reelection for the sake of presidential independence. He frequently operated as the nation's chief diplomat and shaped its aspirations in foreign affairs. Through a skillful use of the press and in widespread travels, he took the presidency to the American people. In these and other ways, he unwittingly taught his successors new uses of power and techniques of leadership. The solipsistic and ham-handed Grover Cleveland took cues from Harrison, but William McKinley proved one of his most astute students. As a member of the Fifty-first Congress, McKinley watched Harrison firsthand. A half decade later, borrowing much from Harrison's methods and purposes but unburdened by many of his obstacles and shortcomings, McKinley fashioned a popular and successful administration. Scholars may regard the latter man as the first modern president, but Benjamin Harrison had clearly pointed the way.