Presidency of Theodore Roosevelt on September 14 , 1901 , when Theodore Roosevelt became the 26th President of the United States upon the assassination and death of President William McKinley , and ended on March 4 , 1909 . Roosevelt had been the Vice President of the United States for only days when he succeeded to the presidency . A Republican , he ran for and won a full four-year term as president in 1904 , easily defeating Democratic nominee Alton B. Parker . After the Republican victory in the 1908 presidential election , Roosevelt was succeeded by his protégé and chosen successor , William Howard Taft
assassination and death of President William McKinley
Assassination of William McKinley
Presidency of Theodore Roosevelt