Theodore Roosevelt was a leader.
Theodore Roosevelt Jr. ( [ ˈroʊzəvɛlt ] ; October 27 , 1858 -- January 6 , 1919 ) was an American statesman , author , explorer , soldier , naturalist , and reformer who served as the 26th President of the United States from 1901 to 1909 . As a leader of the Progressive movement , he championed his `` Square Deal '' domestic policies , promising the average citizen fairness , breaking of trusts , regulation of railroads , and pure food and drugs .