Roosevelt was vacationing in Isle La Motte, Vermont,[133] and traveled to Buffalo to visit McKinley in the hospital. It appeared that McKinley would recover, so Roosevelt resumed his vacation in the Adirondack Mountains.[134] When McKinley's condition worsened, Roosevelt again rushed back to Buffalo. McKinley died on September 14, and Roosevelt was informed while he was in North Creek; he continued on to Buffalo and was sworn in as the nation's 26th president at the Ansley Wilcox House.[135]
McKinley's supporters were nervous about the new president, and Ohio Senator Mark Hanna was particularly bitter that the man he had opposed so vigorously at the convention had succeeded McKinley. Roosevelt assured party leaders that he intended to adhere to McKinley's policies, and he retained McKinley's Cabinet. Nonetheless, Roosevelt sought to position himself as the party's undisputed leader, seeking to bolster the role of the president and position himself for the 1904 election.[136]  The vice presidency remained vacant, as there was no constitutional provision for filling an intra-term vacancy in that office (prior to the 25th Amendment in 1967).
Shortly after taking office, Roosevelt invited Booker T. Washington to dinner at the White House. 