Of a prosperous and distinguished family, Theodore Roosevelt was educated by private tutors and traveled widely. He was a delicate youth, and his determined efforts to overcome this had a marked effect on his character. After graduating (1880) from Harvard, he studied law at Columbia.
Roosevelt's interest was drawn to politics, and while serving (1882–84) in the New York state legislature as a Republican, he strongly opposed the nomination of James G. Blaine for the U.S. presidency. After Blaine's nomination, however, Roosevelt supported him, and that lost him much of his political backing. Discouraged by this turn of events, and bereaved by the deaths (1884) of his mother and his wife, Alice Hathaway Lee, Roosevelt retired to his ranch in the Dakota Territory.
He returned (1886) to New York City and ran as the Republican candidate for mayor against Henry George and Abram S. Hewitt; he came in third. He became increasingly important in Republican party politics. Appointed (1889) by President Benjamin Harrison as a member of the Civil Service Commission, he was noted for his vigor in the post until he resigned in 1895. As head (1895–97) of the New York City police board, he attempted to clean up the notoriously vice-ridden city, accomplishing little but nevertheless gaining public notice by his advocacy of reform.
In 1897 he returned to federal office as Assistant Secretary of the Navy under President McKinley. An ardent supporter of U.S. expansion, he worked toward putting the U.S. navy on a war basis for the coming war with Spain. After the outbreak of the Spanish-American war, he resigned to organize, with Leonard Wood, the volunteer regiment that won fame as the Rough Riders. Returning from Cuba a popular hero, Roosevelt ran (1898) for the governorship of New York state, winning by a small margin. Republican "boss" Thomas C. Platt had supported him in his candidacy, but after Roosevelt's inauguration the two differed when Roosevelt imposed taxes on corporation franchises. It was at least partially to shelve Roosevelt that Platt backed his nomination as Vice President in 1900. The McKinley-Roosevelt slate was elected, but Roosevelt served as Vice President only a few months. McKinley was assassinated, and Roosevelt became (Sept. 14, 1901) President shortly before his 43d birthday, making him the youngest person to hold that office. (John F. Kennedy was the youngest person to be elected President.)