Final answer:
John G. Roberts, Jr. is the current Chief Justice of the Supreme Court, having been nominated by President George W. Bush and serving since 2005.
Step-by-step explanation:
The current Chief Justice of the Supreme Court is John G. Roberts, Jr.
The Supreme Court consists of one chief justice and eight associate justices, all serving lifetime appointments after nomination by the president and confirmation by the Senate.
John Roberts, nominated by President George W. Bush, has served as Chief Justice since 2005. Although he is considered a part of the Court's more conservative wing, Roberts has been known to rule in less predictable ways at times, emphasizing the independent nature of the judiciary.