The president who appointed the most Supreme Court justices was George Washington, who appointed 10 justices to the Supreme Court. Franklin D. Roosevelt comes close with 9 appointments, but Washington holds the record for the most justice appointments in U.S. history.

Key Details:

• George Washington appointed 10 justices including notable figures such as John Jay and Samuel Chase.
• Franklin D. Roosevelt appointed 9 justices during his four terms.
• Other presidents with a high number of appointments include Andrew Jackson and William Howard Taft, each with 6 appointments.
• In contrast, several presidents such as William Henry Harrison, Andrew Johnson, Zachary Taylor, and Jimmy Carter did not have any Supreme Court justices confirmed during their presidencies.

This shows that Washington, as the first president, had the longest opportunity and greatest influence in shaping the early Supreme Court.