Since the Civil War, much of the concern over civil rights in the United States has focused on efforts to extend these rights fully to African Americans. The first legislative attempts to assure African Americans an equal political and legal status were the Civil Rights Acts of 1866, 1870, 1871, and 1875. Those acts bestowed upon African Americans such freedoms as the right to sue and be sued, to give evidence, and to hold real and personal property. The 1866 act was of dubious constitutionality and was reenacted in 1870 only after the passage of the Fourteenth Amendment. The fourth Civil Rights Act attempted to guarantee to the African Americans those social rights that were still withheld. It penalized innkeepers, proprietors of public establishments, and owners of public conveyances for discriminating against African Americans in accommodations, but was invalidated by the Supreme Court in 1883 on the ground that these were not properly civil rights and hence not a field for federal legislation.

After the Civil Rights Act of 1875 there was no more federal legislation in this field until the Civil Rights Acts of 1957 and 1960, although several states passed their own civil-rights laws. The 20th-century struggle to expand civil rights for African Americans involved the National Association for the Advancement of Colored People, the Congress of Racial Equality, the Urban League, the Southern Christian Leadership Conference, and others. The civil-rights movement, led especially by Martin Luther King, Jr., in the late 1950s and 60s, and the executive leadership provided by President Lyndon B. Johnson, encouraged the passage of the most comprehensive civil-rights legislation to date, the Civil Rights Act of 1964; it prohibited discrimination for reason of color, race, religion, or national origin in places of public accommodation covered by interstate commerce, i.e., restaurants, hotels, motels, and theaters. Besides dealing with the desegregation of public schools, the act, in Title VII, forbade discrimination in employment. Title VII also prohibited discrimination on the basis of sex.

In 1965 the Voting Rights Act was passed, which placed federal observers at polls to ensure equal voting rights. The Civil Rights Act of 1968 dealt with housing and real estate discrimination. In addition to congressional action on civil rights, there was action by other branches of the government. The most notable of these were the Supreme Court decisions in 1954 and 1955 declaring racial segregation in public schools unconstitutional and the court's rulings in 1955 banning segregation in publicly financed parks, playgrounds, and golf courses.

In the 1960s women began to organize around the issue of their civil rights (see feminism). The federal Equal Pay Act was passed in 1963, and by the early 1970s over 40 states had passed equal pay laws. In 1972 the Senate passed an Equal Rights Amendment (ERA) intended to prohibit all discrimination based on sex, but after failing to win ratification in a sufficient number of states, the ERA was abandoned. Since the 1970s a number of gay-rights groups have worked, mainly on the local and state levels, for legislation that prevents discrimination in housing and employment (see gay-rights movement). In a further extension of civil-rights protection, the Americans with Disabilities Act (1990) barred discrimination against disabled persons in employment and provided for improved access to public facilities.