Sandra Day O'Connor (1930-) was the first female Associate Justice of the U.S. Supreme Court, serving from 1981 to 2006 as a moderate conservative known for her thoughtful opinions. She was a significant figure in many crucial court decisions, often acting as a swing vote, and received the Presidential Medal of Freedom in 2009. After retiring to spend more time with her family, O'Connor continues to be recognized for her pioneering contributions to the legal field.