The President of Chile is both the chief of state and the head of government. Under the current constitution (1980), the President is elected by popular vote to serve for a period of four years, with immediate re-election being prohibited. The shorter period (previously the term was six years) allows for parliamentary and presidential elections to be synchronized. This is not unique: France reduced its presidential terms in 2002, from seven to five years, for the same reason.
Note: In bold, effectively held the seat of President or Supreme Director. In italics, held the seat in an interim manner or temporarily due to vacancy. † means date of death of the seat-holder.