The aim of this article is to analyse the dynamics and intensity of diplomacy at the highest level in the practice of Poland’s foreign policy after 1989. From the perspective of international law, high-level diplomacy is understood as a form of special diplomatic mission. A defining characteristic of such a mission is the status of the individual leading it. Diplomatic studies, meanwhile, employ the concept of summit diplomacy. For the purposes of this article, the term diplomacy at the highest level will be used, as it integrates both the international legal perspective and the approach of diplomatic studies. In the article the relationship between a state’s stage of development and the intensity of its presidents’ international activity is examined. The following research questions are posed: (1) What was the intensity of international activity by Polish presidents? (2) What were the factors influencing the international activity of individual Polish presidents? The theoretical framework of this article is interdisciplinary, combining international legal approaches, diplomatic studies, and political science perspectives. The adopted research strategy allows for the use of both quantitative methods (quantitative data analysis) and qualitative methods (comparative method and case study). The paper concludes that the most active period of the presidency after 1989 was characterized by significant events, such as accession to the North Atlantic Treaty Organisation and the European Union, which undoubtedly required increased efforts on the international stage. Additionally, three main types of factors influencing the international activity of Polish presidents after 1989 can be identified: i nternal factors – relating to the President’s position within the constitutional system; international factors – connected to the state of the global environment; subjective factors – such as the President’s knowledge and understanding of international affairs.