be the power behind the throne

To be the person or people who have true control or great influence on a leader, but who are not officially or publicly in charge. The president's charisma and likability got him elected, but his team of advisors is the real power behind the throne. A: "Why did you marry a fool like him in the first place?" B: "So I could be the power behind the throne, my dear." Who is truly the power behind the throne here? I'm starting to think the prime minister is a mere puppet.

be the (real) power behind the ˈthrone

be the person who really controls a family, business, country, etc., even though people think somebody else controls it: It’s not the president who makes the important decisions; his wife is the real power behind the throne.