Who is the chief officer of the legislative branch?

The chief officer of the legislative branch in the United States is the Speaker of the House of Representatives. The Speaker is responsible for leading the House, managing its legislative agenda, and representing the House in its relations with the Senate and the President. In the context of the U.S. Congress, the Vice President also plays a significant role in the legislative branch as the President of the Senate, but the Speaker is the primary leader in the House.