In the Supreme Court's 230-year history, four women have served as Supreme Court justices. A total of 114 justices have ever served on the Supreme Court, meaning that women make up just 3.5% of the total. The first woman seated on the Supreme Court did not do so until 1981, and even today, the court does not approximate a gender or racial balance of the country as a whole. One early change to the court was the form of address from "Mr. Justice," previously used in the Supreme Court for associate justices, to the more gender-inclusive single word "Justice."

The four women justices—all associates—who have served on the Supreme Court are Sandra Day O'Connor (1981–2005); Ruth Bader Ginsburg (1993–present); Sonia Sotomayor (2009–present) and Elena Kagan (2010–present). The latter two, nominated by President Barack Obama, each earned a distinctive footnote in history. Confirmed by the U.S. Senate on August 6, 2009, Sotomayor became the first Hispanic on the Supreme Court. When Kagan was confirmed on August 5, 2010, she changed the gender composition of the court as the third woman to serve simultaneously. As of October 2010, the Supreme Court is one-third female for the first time in its history. Together, the justices' histories represent successes against uncountable odds beginning with their acceptance into law school.

Sandra Day O'Connor

Justice Sandra Day O'Connor is the 102nd person to sit on the Supreme Court. Born in El Paso, Texas on March 26, 1930, she graduated from Stanford Law School in 1952, where she was a classmate of future Justice William H. Rehnquist. Her career included civilian and private practice, and, after moving to Arizona, she became active in Republican politics. She was an assistant attorney general in Arizona and ran for and won a state judgeship before being appointed for the Arizona Court of Appeals.

When Ronald Reagan nominated her for the Supreme Court, he was fulfilling a campaign promise to nominate a woman. After a unanimous confirmation vote in the Senate, O'Connor took her seat on August 19, 1981. She generally took a middle road on many issues, finding in favor for state's rights and tough rules on crime, and was a swing vote on rulings for affirmative action, abortion, and religious neutrality. Her most controversial vote was that which helped suspend Florida's presidential ballot recount in 2001, ending Al Gore's candidacy and making George W. Bush president. She retired from the court on January 31, 2006.

Ruth Bader Ginsburg

Justice Ruth Bader Ginsburg, the 107th justice, was born March 15, 1933, in Brooklyn, New York, and studied law at Harvard and Columbia University Law schools, graduating from Columbia in 1959. She worked as a law clerk, and then at the Columbia Project on International Civil Procedure in Sweden. She also taught law at Rutgers and Columbia universities, before heading up the Women's Rights Project of the American Civil Liberties Union (ACLU).

Ginsburg was appointed a seat on the U.S. Court of Appeals by Jimmy Carter in 1980, and was nominated to the Supreme Court by Bill Clinton in 1993. The Senate confirmed her seat by a vote of 96 to 3, and she was sworn in on August 10, 1993. Her important opinions and arguments reflect her lifelong advocacy for gender equality and equal rights, such as Ledbetter versus Goodyear Tire & Rubber, which led to the Lilly Ledbetter Fair Pay Act of 2009; and Obergefell v. Hodges, which ruled same-sex marriage legal in all 50 states.

Sonia Sotomayor

The 111th Justice, Sonia Sotomayor was born on June 25, 1954, in the Bronx, New York City and earned her law degree from Yale Law School in 1979. She served as a prosecutor in the New York County District Attorney's office and was in private practice from 1984 to 1992.

She became a federal judge in 1991, after nomination by George H. W. Bush, and joined the U.S. Court of Appeals in 1998 nominated by Bill Clinton. Barack Obama nominated her for the Supreme Court, and after a contentious Senate battle and a vote of 68–31, she took her seat on August 8, 2009, as the first Hispanic justice. She is considered part of the liberal bloc of the court, but places Constitutional and Bill of Rights principles ahead of any partisan considerations.

Elena Kagan

Justice Elena Kagan is the 112th justice on the court, born April 28, 1960 on the Upper West Side of New York City. She earned her law degree from Harvard University in 1986, and worked as a law clerk for Justice Thurgood Marshall, was in private practice, and taught at the University of Chicago and Harvard Law Schools. From 1991–1995, she worked at the White House as a counsel for Bill Clinton, eventually achieving the role of Deputy Director of the Domestic Policy Council.

Justice Kagan was Dean of the Harvard Law School in 2009 when she was selected as Solicitor General by Barack Obama. She was nominated to the Supreme Court by Obama, and after a battle in the Senate, she was confirmed by a 63–37 vote and took the seat on August 7, 2010. She has had to recuse herself on many decisions, the result of having worked in the executive branch for Bill Clinton, but voted to support the Affordable Care Act in King v. Burwell and same sex marriage in Obergefell v. Hodges.