Roosevelt expanded the Navy and sent the Great White Fleet on a world tour to project American naval power. His successful efforts to broker the end of the Russo-Japanese War won him the 1906 Nobel Peace Prize, making him the first American to ever win a Nobel Prize.

During his first 100 days as president, Roosevelt spearheaded unprecedented federal legislation and directed the federal government during most of the Great Depression, implementing the New Deal in response to the most significant economic crisis in American history.

Two distantly related branches of the family from Oyster Bay and Hyde Park, New York, rose to global political prominence with the presidencies of Theodore Roosevelt (1901–1909) and his fifth cousin Franklin D. Roosevelt (1933–1945), whose wife, First Lady Eleanor Roosevelt, was Theodore's niece.

Age of presidents The median age at inauguration of incoming U.S. presidents is 55 years. The youngest person to become U.S. president was Theodore Roosevelt, who, at age 42, succeeded to the office after the assassination of William McKinley. The oldest person inaugurated president was Joe Biden, at age 78.