There are many reasons why the Civil Rights movement took off in the 1960s and not earlier. It is tempting to attribute this solely to the leadership of Martin Luther King Jr., and he was an extremely important catalyst and pragmatic visionary integral to the success of the movement. However, no individual alone can carry off social change unless the groundwork has been laid ahead of time and the right circumstances are in place at the time.
Since the end of Reconstruction, African Americans had been pursuing a more equitable and just relationship with white people in the US. They had tried being accommodating, a stance pushed in the late nineteenth and early twentieth centuries by African American leader Booker T. Washington. Washington believed that by accepting second-class citizenship, such as by giving up the right to vote in the South, in return for access to more economic well being, African Americans would eventually earn enough money to win the respect of whites and, therefore, more rights. By the aftermath of World War II, however, this was palpably a failed theory.
World War II was a catalyst for the Civil Rights movement. African Americans were upset that they fought against Fascism only to return to a country that treated them with discrimination and hatred, much as the Nazis had treated the Jews. At the same time, the post-war US was prospering, with a huge burst of economic growth. Black people were increasingly questioning why they were not allowed to share in this bounty—and white people, now economically comfortable themselves, were willing to be generous.
Further, communist countries, notably the USSR, were making much propaganda hay out of publicizing—with photos—the deplorable conditions black people lived in in the US, in order to discredit ideas that capitalism was a better system than communism. Finally, Gandhi had recently paved the way to success using nonviolent protest in India: leaders such as Martin Luther King Jr. studied and employed his methods. At the same time, a generalized attitude of idealism among young white Americans and the success of the Trappist monastic movement, which trained Catholics so they could then reenter the world working for idealist movements, provided a groundswell of support for Civil Rights.
Since the Depression and before, blacks had been preparing for a better day. King and his circle strategized carefully in the 1950s and were relentlessly self-disciplined and on message. This led finally to acceptance of the need for the federal Civil Rights legislation in the 1960s, which President Johnson backed. This acceptance was accelerated, too, by the unrest that grew in black communities, leading to rioting in the mid-1960s, and the general social upheaval that emerged in the late 1960s. The time was ripe for change in the 1960s, and change did come.