We typically think that the Civil Rights Movement started with Rosa Parks in late 1955. While this is true in many ways, we should not ignore the fact that there were important changes between the end of World War II and 1955.
There are only two milestones from this period that most Americans know about. These are the debut of Jackie Robinson as the first African American in Major League Baseball in 1947 and the 1954 Supreme Court decision in Brown v. Board of Education, which made segregation in public schools illegal. However, there were other changes that helped to improve conditions for African Americans during this time.
Baseball was not the only thing that desegregated during these years. In 1949, the army adopted a new policy that allowed African Americans to serve in any position for which they were qualified. The navy and the air force did the same. This led to the integration of military units during the Korean War. In addition, in 1948 President Harry Truman issued an executive order that banned discrimination in federal employment. In terms of housing, that year also saw the Supreme Court issue a ruling in Shelley v. Kraemer that prevented governments from enforcing private contracts (called “restrictive covenants”) that prohibited whites from selling their homes to blacks. This made it more possible for neighborhoods to become integrated. In 1950, the Supreme Court decided Henderson v. United States, ruling that segregation in railroad dining cars was illegal.
All this is not to say that things improved tremendously for African Americans during these years. There was still a great deal of discrimination and segregation. However, there were advances made during these years that did improve conditions for African Americans.