How long can you be in the supreme court justice?

Answer 1

Although neither the constitution nor federal law prohibits non-citizens from serving on the US Supreme Court, it's unlikely the President would ever nominate a non-citizen to the Court or that the Senate would approve such a nomination. In practice, yes, you would undoubtedly have to be a citizen.

Answer 2

Although all members of the current US Supreme Court have served on the US Court of Appeals, there is no requirement that they do so, let alone a specification about the number of years.

Answer 3

A supreme court justice is a position that is held for life. The justice can offer to step down at any time though, most likely for reasons like retirement or bad behavior.