A total of 41 justices (10 Chief Justices and 31 Associate Justices) of the 112 seated (36.6%) had no judicial experience before joining the US Supreme Court. The following list includes only US...
The President can not appoint a new judge unless a vacancy occurs or Congress creates a new position on the court. The Supreme Court is not involved in either case.
No, you do not. Elena Kagan was recently nominated and confirmed by the senate without prior experience as a Judge. William Rehnquist also had no prior judicial experience.