Simplify the following text for a Grade 6 native English-speaking person.
Original: The Chief Justice of the United States is the head of the United States federal court system ( the judicial branch of the federal government of the United States ) and the chief judge of the Supreme Court of the United States . The Chief Justice is one of nine Supreme Court justices ; the other eight are the Associate Justices of the Supreme Court of the United States .
Simplified: The Chief Justice of the United States is the senior judge of the Supreme Court of the United States .