administrator, executive

someone who manages a government agency or department

• commissioner — a government administrator
• prefect — a chief officer or chief magistrate
• Secretary General — a person who is a chief administrator (as of the United Nations)
• triumvir — one of a group of three sharing public administration or civil authority especially in ancient Rome
• Raffles, Sir Thomas Raffles, Sir Thomas Stamford Raffles — British colonial administrator who founded Singapore (1781-1826)
• Stuyvesant, Peter Stuyvesant, Petrus Stuyvesant — the last Dutch colonial administrator of New Netherland; in 1664 he was forced to surrender the colony to England (1592-1672)

• head, chief, top dog — a person who is in charge