During the summer of 1964, thousands of civil rights activists, many of them white college students from the North, descended on Mississippi and other Southern states to try to end the long-time political disenfranchisement of African Americans in the region. Although black men had won the right to vote in 1870, thanks to the Fifteenth Amendment, for the next 100 years many were unable to exercise that right. White local and state officials systematically kept blacks from voting through formal methods, such as poll taxes and literacy tests, and through cruder methods of fear and intimidation, which included beatings and lynchings.

Freedom Summer marked the climax of intensive voter-registration activities in the South that had started in 1961. Organizers chose to focus their efforts on Mississippi because of the state's particularly dismal voting-rights record: in 1962 only 6.7 percent of African Americans in the state were registered to vote, the lowest percentage in the country. By mobilizing volunteer white college students from the North to join them, the coalition scored a major public relations coup as hundreds of reporters came to Mississippi from around the country to cover the voter-registration campaign.

The well-publicized voter registration drives brought national attention to the subject of black disenfranchisement, and this eventually led to the 1965 Voting Rights Act, federal legislation that among other things outlawed the tactics Southern states had used to prevent blacks from voting. Freedom Summer also instilled among African Americans a new consciousness and a new confidence in political action.