SCOTUS Seniority:

Supreme Court Justices are appointed after being nominated by the President of the United States and confirmed by the Senate. The Chief Justice (currently John Roberts) is chosen by the President and is the most senior, by definition. The eight associate justices are seated by their seniority in the court (the length of time served, not their age). Justices serve for life unless they retire, resign, receive senior status, or are impeached. The newest Justice, Ketanji Brown Jackson, took the oath of office on June 30, 2022.

Click here for an interactive look at all the justices who have served since 1789.