Architect of the Brown decision, the NAACP is the oldest, largest, and arguably most significant civil rights organization. Formed in 1909, it joined whites and blacks who opposed racial violence and Booker T. Washington's conciliatory leadership and demanded “the equal protection of the laws.” W. E. B. Du Bois, director of publicity and research, edited The Crisis. Its New York national office and board of directors oversaw local and state branches and regional offices.

The Legal Committee (1913) shaped the agenda. It included a national campaign against lynching and lawsuits contesting Jim Crow education, suffrage, housing, employment, criminal justice, and military service. In 1917 James Weldon Johnson became field secretary to organize branches and served as the first black executive secretary (1920–30). In 1940 the board established the NAACP Legal Defense and Educational Fund, Inc. (LDF) for litigation. By 1948 there were “734 branches out of 1,123, a percentage of sixty-five percent,” in the South. Led by Thurgood Marshall and his staff, with lawyers such as Oliver W. Hill of Virginia, LDF won Supreme Court decisions outlawing the “white primary” election (1944), housing “restrictive covenants” (1948), segregated graduate education (1950), and public school segregation (1954).

Buffeted by challenges since 1954, the NAACP has been resilient and remains a leading force for racial equality. Financial and policy differences led LDF and the parent body to separate in 1956. However, the NAACP Legal Department under Robert Carter successfully litigated school desegregation and voting rights cases. This paralleled the NAACP's support of organizations using nonviolent strategies as well as its lobbying to secure the 1960s Civil and Voting Rights and Fair Housing laws. Advocating integration and criticizing Black Power politics, its more than half-million membership supported crucial reforms, including court-ordered busing; affirmative action programs; electing liberals, blacks, and other minorities to public office; abolishing police brutality; and ending race and class poverty. NAACP members helped sustain the movement to end South Africa's apartheid system, yet its leadership faltered (due partly to misconduct) and finances weakened. Thanks to board, executive officer, and staff policies implemented in 1995, the NAACP has reclaimed its leading position in the freedom struggle.