Coolidge himself was not versed or deeply interested in world affairs. To handle international issues, Coolidge looked to Treasury Secretary Andrew Mellon, Commerce Secretary Herbert Hoover, and his Secretaries of State, Charles Evans Hughes and, in the second term, Frank B. Kellogg. Neither a Wilsonian internationalist nor an isolationist, Coolidge believed in expanding America's commercial interactions with other nations, policing the Western Hemisphere in keeping with the Monroe Doctrine, and refraining from entangling alliances and participation in the League of Nations. But he favored joining the World Court (although he could not get Congress to agree), and he authorized American representatives--first Charles Dawes, then Owen Young--to help settle continuing European financial issues stemming from World War I. The Dawes Plan introduced mechanisms to balance the German budget, reorganize the Reichsbank, and stabilize the currency. It was later replaced by the Young Plan during the Hoover administration.

Coolidge also signed the Kellogg-Briand Pact, which renounced war as a means of solving conflicts. Named for the U.S. Secretary of State and for French Foreign Minister Aristide Briand, the proclamation carried with it no means of enforcement. Coolidge recognized the essentially symbolic nature of the pact and had doubts that it would actually prevent war. But the pact, which won the signatures of fourteen countries, nonetheless represented a step toward the creation of global protocols that would serve as norms for international behavior in later years, and it brought a Nobel Peace Prize to Kellogg--the second Coolidge administration official, after Charles Dawes for the Dawes Plan, to be so honored.

During Coolidge's term in office, the United States continued to maintain a strong presence and assert influence in Latin America. Direct investments, which rose from $1.26 billion in 1920 to $3.52 billion in 1928, inextricably tied the economies of those countries to America. For example, the United Fruit and Standard Fruit companies controlled most of the revenue of Honduras, and U.S. firms dominated Venezuelan oil production. Control of the Panama Canal and a policy of using troops, when necessary, to safeguard U.S. interests also worked to give the United States the upper hand in the region. In a direct show of influence, U.S. troops trained and maintained a pro-American National Guard in the Dominican Republic and occupied Nicaragua and Haiti with a peacekeeping force of U.S. soldiers throughout the decade. Americans also controlled Cuban politics and the Cuban economy, and the United States nearly came to blows with Mexico over the ownership of Mexican oil fields by American companies.

So embittered were most Latin American leaders over America's policies that the republics of the Western Hemisphere assembled for their triennial conference in Havana, Cuba, in 1928 eager to demand changes in American conduct. In a rare trip overseas, President Coolidge personally traveled to Havana to address the conference and extend an olive branch. Former Secretary of State Charles Evans Hughes, serving as a special envoy, gave a tour de force of a speech that persuaded the delegates to refrain from passing a strong anti-U.S. resolution. Afterward, Kellogg had his legal adviser draft a white paper that argued against direct military intervention in Latin America. Although not a change in policy, it reflected a dawning awareness of the need for change, which would finally come when President Franklin Roosevelt announced a "Good Neighbor Policy" of nonintervention in 1933.