This Special Issue explores the causes, patterns and consequences of presidential activism, defined as the presidents’ use of their formal powers and their attempts to influence politics through informal channels. Examining ‘going public’ strategies, the influence exerted by presidents through informal and formal coordination mechanisms, links to political parties and foreign policy leadership, it argues that presidential activism shapes intra-executive relations, enabling presidents to wield influence beyond their constitutional powers. Presidential activism is facilitated by the presidents’ popularity and role as head of state, particularly in less stable political contexts. These findings underline the need to investigate further various channels of presidential activism and how the citizens and media react to it, both during normal times and crises.