The Constitution provides no criteria or qualifications for federal judges. Technically, a non-lawyer with no legal experience could be appointed to the U.S. Supreme Court.

Congress and the Department of Justice carefully review nominees to determine if they have the requisite degree of professional accomplishment and experience necessary for the lofty position. Most of the judges have a record of outstanding professional achievement, key political connections, and a history of public service in some capacity. Many appellate judges have had some prior judicial experience. For example, all nine justices of the U.S. Supreme Court previously had some form of judicial experience before they served on the U.S. Supreme Court.