The first African American to serve as a Supreme Court Justice in the United States is Thurgood Marshall. Appointed by President Lyndon B. Johnson in 1967, Marshall was a prominent civil rights lawyer who played a critical role in dismantling racial segregation. His most notable case was Brown v. Board of Education, which declared school segregation unconstitutional. As a Justice, Marshall's advocacy for equal rights and his progressive views impacted many significant rulings and laid the groundwork for future advancements in civil liberties.