The primary purpose of this chapter is to examine the impact that Theodore Roosevelt had on the office of the Presidency, and more specifically his possible impact on the formulation and implementation of American foreign policy. Did Roosevelt’s ascension to power mark a significant shift in America’s diplomatic conduct? The chapter will address this question and is divided into four sections. The first section offers a concise contextualization of the periodization being treated in this analysis. There then follows three distinct subchapters that examine the evolution of the president’s role in foreign policy formation. The first of these will explore the foreign policy machinery that existed during Grover Cleveland’s second term (1893-1897) and William McKinley’s ill-fated spell in office (1897-1901). The second subchapter will deal with Theodore Roosevelt’s two terms (1901-1909), with the third section analyzing the presidencies of William Howard Taft (1909-1913) and Woodrow Wilson (1913-1921). The aim is to determine whether Roosevelt’s presidency marked a decisive shift from his predecessors as to how American diplomacy was crafted and executed. Did the role of the Secretary of State diminish in line with an increase in the power of the Presidency? In addition, it is intended to explore whether Roosevelt’s style of diplomacy was carried on by his immediate successors, Taft and Wilson.