Rubuta ci gaba ga wannan sakin layi - Roosevelt ya yi aiki a matsayin mataimakin sakatare na sojan ruwa da kuma gwamnan New York kafin ya lashe zaben a matsayin William McKinley na gudana a zaben shugaban kasa na 1900. Roosevelt ya zama shugaban kasa bayan kisan McKinley
ta hanyar anarchist Leon Czolgosz a Buffalo, New York; Czolgosz ya harbe McKinley a ranar 6 ga Satumba, 1901, kuma McKinley ya mutu a ranar 14 ga Satumba. An rantsar da Roosevelt a ranar mutuwar McKinley a gidan Ansley Wilcox a Buffalo. John R. Hazel, Alkalin Gundumar Amurka na Yammacin Gundumar New York, ya ba da rantsuwar ofishin. Kasancewa 'yan makonni kaɗan daga ranar haihuwarsa ta 43, Roosevelt ya zama shugaban ƙasa mafi ƙanƙanta a tarihin Amurka, bambancin da ya ci gaba da riƙewa.