Theodore Roosevelt

Summary

Theodore Roosevelt became the youngest U.S. president in 1901 at age 42 after William McKinley's assassination. He used federal power to regulate big business, earning the nickname 'trust-buster,' and championed conservation by creating national parks and forests. Roosevelt dramatically expanded American influence abroad, mediating international disputes, building the Panama Canal, and establishing the U.S. as a global power. His energetic, progressive leadership redefined the presidency as an active force for reform.