In Chile, military subordination to civilians has been a difficult, gradual, and unaccomplished process. Using a qualitative approach, this case study analyzes how a head of state—President Ricardo Lagos (2000–2006)—introduced without constitutional prerogatives important changes in military subordination to civilian authorities. Based on political leadership studies and civil–military relations theory, we analyze the constitutional reforms that ended military presence in the Senate, and two policy changes—military acquisitions and human rights. We argue that President Lagos' transformation type of effective leadership made these changes possible.