Thurgood Marshall had a monumental impact on civil rights in the United States, particularly through his role as a lawyer and the first African American Supreme Court Justice. He was instrumental in the landmark case Brown v. Board of Education, which declared racial segregation in public schools unconstitutional. His legal battles fought against discrimination and advocated for equal protection under the law. As a Supreme Court Justice, Marshall continued to champion civil rights, influencing decisions that advanced justice and equality for marginalized groups, thereby leaving an enduring legacy in American legal history.